What's your strategy for waking up early without feeling like garbage?

get 10-12 hours of sleep before, works like a charm, I get tired around 3pm and go to sleep at 7-8. wake up at 4-6 and have no free time. but I manage to get to school on time, and all I have to do is sacrifice my entire personal life.

Get up. Don't fuck around with snooze, those few extra minutes don't help.
Allow time to reward yourself for getting up. For me it's word puzzles and coffee before I get ready.

Wake up early consistently every day for at least a week before then. Also go to sleep early every day for a week before then.
- If I might add: Jump out of bed the moment your timer goes off. No 8 timers to wake up bullshit. Just one. When it rings -> you’re already on your way to the bathroom.
  It’s kinda inhumane the first few times but the shock will wake you up. You will be too preoccupied with shivering and can’t feel like shit.
- This is technically the best advice.
  I just got back from 4 weeks in a +5 timezone and after a week home I'm still waking up at 5:00 fresh as a daisy.
  So if you've got the money, time, inclination maybe go for a trip to help.
- This is not the way.

I do several things in conjunction.
I plan when I need to go sleep using either sleepyti.me or wakeupti.me and set my alarms accordingly. Setting your alarm to align with your sleep patterns makes the act of waking up much easier.
I set my phone on my desk away from my bed. The reasoning is two-fold; it forces me to get up and out of bed to dismiss my alarm(This works extra well if you make it a habit to get dressed as soon as you're out of bed.), and it prevents me from laying in bed while playing on my phone.
I wake up at the same time every day. Consistency is paramount managing sleep.
I only sleep in my bed. I don't do anything else. This builds an association to automatically get sleepy when you get in bed because the only thing you in bed is sleep. Your brain knows what to expect and just does it. Sort of like how some guys get excited when they see their girlfriend tie her into a ponytail.

You can't make yourself sleep. You can make yourself get up. Force yourself to get up early the going to bed early part will take care of itself.
Oh and you should stop drinking liquids a couple of hours before bed. Unless your a man over 50, in that case if you want to sleep through the night you'll have to avoid any fluids after Tuesday.
- Force yourself to get up early the going to bed early part will take care of itself.
  Maybe for you, for me I get exhausted in the middle of the day, and when night rolls around I get a second wind that lasts until the wee hours anyway.
- YMMV but personally, I've never found that no liquids thing to be good advice. My body seems to wake me up if I need to pee in between sleep cycles, and I have no problem getting back to sleep. But I can get busy and forget to drink enough, and then realize how thirsty I am as I'm getting ready for bed.
- This is not the way.

So far it looks like the consensus is: wake up early and don't feel like garbage. 😆
- The masses do not always have the solution. Genetics is a harsh mistress. We are the ones that take the late watch. We protect the tribe at night. Today, we are despised unless we fulfill the meager agendas... But we are not without worth. Chin up, friends. We may have our day.
  
  Best answer here.

Eat relatively healthy, stay hydrated, and get 7 hours of sleep.
cracks a beer and stuffs a jalapeño popper in his gob
- Do as I say and not as I do
  
  Knowing the right steps is not the same as doing them. That is only hypocritical if you judge others for what you won't do. Otherwise it is just being self aware.
  
  " I ain't an athlete, lady. I'm a baseball player." - John Kruk absolute unit and legend First Baseman.
- This is not the way.

Don't forget that whatever method you adopt repetition and time are the most help. Like exercise or quitting smoking, eventually your body will get the message that now it's time to go to sleep, and now it's time to wake up. But it takes practice to make a habit. I heard once a habit takes on average 36 consecutive attempts, so expect at least a month or more before you don't feel like you're trying anymore and it just happens on it's own.

I wake up between 4-5AM every single day of the week, and all year long. I don't even need an alarm clock. I can go to sleep at anytime
No screen before bed. No computer, no phone, no tablet, no TV (we don't own a TV, so we don't have much choice here ;). What do I do instead? I read a book, journal, write, chat with my spouse or friends, play chess or board games,... I do various stuff just not on a screen. Not even using a Kindle.
No coffee in the evening. No alcohol at all (evening as well as in the day: I was an alcoholic many, many years ago). No soda either. Either I'll drink water or herbal tea.
Light & healthy diner. I don't stuff my stomach, don't eat garbage pre-packaged industrial 'food' either (this alone was a huge change for me, the day I quit eating that absolute turd a few years ago and my health has jumped through the roof, pre-packaged food is just poison in a fancy packaging and a lot of marketing, I would not be surprise if it was to become the tobacco of the XXI health-wise).
No snacking, no candy, chips, or whatever.
At least one long walk during the day. Every day.
- My wife has to eat a snack with her medicine she takes before bed or she gets nauseas. I have struggled to find an alternative to goldfish because I agree, it's garbage. Any thoughts?
  
  My wife has to eat a snack with her medicine she takes before bed or she gets nauseas. I have struggled to find an alternative to goldfish because I agree, it’s garbage. Any thoughts?
  What is a goldfish (beside a fish, I mean)? If you mean an alternative to snack, has she tried fresh fruits (an apple, pear, a few grapes,...) or maybe things like nuts? The idea being to no eat heavily processed food at all and not too much of anything. If she is not into fresh fruits (that would be sad), at worst I would suggest a slice of fresh bread (here again not the industrial hyper-processed kind of bread, real bread) with something, maybe a little jam?
  
  I've had great luck with rice cakes, unsalted pretzels, or natural peanut butter on toasted bread of some sort.

Be born different, my friend. Never regret how you were built, however, as it is prized and unique.

For some reason if i go to sleep at 0000 i wake naturally quite early. But if i go later or earlier, i sleep way too much. I went to bed at 0000 for about a year as I had things to wake up for and at some point i started to wake in time or earlier even without alarm. It still seems to work even after sleeping way too late for many months.
While i had work, i also woke up about hour before i had to leave just so i can "nap" for hour. I would wake up, brush my teeth and put my clothes on so i can just leave and then set alarm for about 1h. I dont know if it was good idea or not, but it felt like it worked.
So going to bed at same time each or at least most nights and getting enough sleep might help. And definitely dont do anything extra in bed while trying to sleep like using phone, it will surely lower the quality of sleep.

No drinking definitely helps me.
- Ignorance is what helps you.

Routine. Go to bed at the same time. Reduce electronics before bed.
- This is ignorance. It is not the way for many of us.

The only thing I've tried that actually works: apps like Sleep Cycle.
The app tracks your sleep, but that's secondary for you. What you want out of it is the alarm part. You give it an interval of time when you want to wake up, and it'll do it based on which sleep stage you're in.
The idea is simple - you have different stages of sleep. Sometimes you're in deep sleep, sometimes in REM (rapid eye movement), sometimes in light sleep - there may be others, idm. You want to wake up from light sleep, that's when you feel the most fresh. Waking up from deep sleep you're all groggy and still half asleep. So the app determines when you're in the lightest sleep, and it plays an alarm gradually, so that you're not just scared awake.
You can read more here: https://www.sleepcycle.com/features/smart-alarm-clock/
The thing is, this feature is actually not why I got the app. I wanted to track my sleep, I didn't really care about how I woke up. But I honestly just found it easier to wake up with this, so now I recommend it.
- That sounds awesome, I wish I could use that. Unfortunately my fiancée and I have very different sleeping habits and I imagine one of us is going to be waking up at the wrong point in the sleep cycle. Sounds like a great idea though
  
  If you hold the phone on your side of the bed, it should theoretically record your sleep pattern, not hers. So it should play the alarm when you're in light sleep, not her. And since the alarm starts off with low volume, there's a high chance you will be the first to hear it - she might not even notice it before you're already up. Unless you're a heavy sleeper and she isn't, in which case - yeah, it might not work.

I've redefined what early means. My work starts at 2pm so waking up at midday is early and it feels slightly better

Go to bed early if possible. Coffee if I can't and then try to stay away from other humans till I can be less of an asshole.
If I'm shifting my schedule, I'll try and aim for 9 -10 hours in bed until my body adapts, then it's back to the 6 to 7 I usually get.

I do the classic where I get anxious about having to be up and actually alert, and don't sleep as a result. Don't really recommend.
- What is your point of no return? For me it's 3 in the morning. If I'm still awake, i better stay awake...
  
  That makes no sense, any sleep is better than no sleep

Get old.

I'm pretty sure that's a physical impossibility in the known laws of the universe. Best I can do is wake up earlier to give me time to feel like garbage, but then be fine by the time I have to do anything.

My puppy. First thing at 0430, get up, take him out to pee, get dressed, go for a short walk, inside for training (all kibble is used to training), then hand him over to my wife at 0530. That hour really gets me going, but only because I want to give the puppy three best life, which also brings me joy!

I just need a good 7 hours of sleep at least. You can't cheat sleep duration. Eventually, you'll need to catch up if you aren't getting enough and it'll compound the bad feeling.
I fall asleep faster if I've had a drink, but not necessarily better. I might wake up in the middle of the night if I do.
Pattern is important. If you usually wake up at 9 or 10am and want to wake up at 5 or 6am instead, you'll probably have some meh feeling regardless, but the more you do it, the better it gets. Maybe consider moving your normal wake up time closer to the earliest times you want to wake up.

Make a clone of yourself to wake up early for you

Do you mean regularly or exceptionally?
If I need to get up early as an exception I just go to bed earlier and automatically tend to wake up before my early alarm.

Waking up early and feeling like garbage is amplified for me by drinking, staying up late, eating just before bed, watching screens until I fall asleep, having inconsistent hours over the weekend, and getting accustomed to snooze.
Avoiding these things seems to help.
Having kids and hearing them do stuff early in the morning seems to get me moving early.

My estradiol alarm. Starting the day has never felt so good.
- Apologies in advance, for I am kind of dumb, but what does this mean?
  
  Estradiol is a pill I take twice daily. It is hormone therapy to make me more feminine (I'm a transgender woman). The side effect is it makes me really happy about myself and life. Chronic depression is a thing of the past.

How early? When I had to get up at 5, it just sucked no matter what. At 7? Just do it for a couple of weeks until you can be sleepy at 11pm, it will work itself out.
- It doesn't just work itself out for everyone.
  
  Sure, but it's certainly the first thing to try. Get up when you need to, go to bed when you get sleepy. And I do think there is some "7:00" for everyone, some earliest time that can feel good, unless you have a literal sleep disorder, in which case asking the internet doesn't seem like the best strategy.

I don't. I'm not a morning person and I'm always garbage if I try to be.

Actually go to bed very, very early. I don't mean "23:00 instead of midnight" early, but at like 19:00. My body is used to going to bed at 22:00-23:00 and then 2 hours of videos and livestreams. Instead, it gets 3 hours till 22:00, at the end it slips into disbelief that it should sleep already, but finally slips into it at 22:00-23:00. And so, 8 hours of sleep at 6:00-8:00. And then either getting up, or resting till 9:00.

Don't have kids

Biphasic sleep. One 5 1⁄2-6 hour block over night, one 90 minute siesta before work.
- I know what biphasic sleep is. But I’m not clear on when you are doing it. Do you get up at like 4 am? For how long?
  Or maybe I just need to know when work starts for you?
  
  6:30am-12pm I am awake
  12pm-1:30pm I am asleep (siesta)
  1:30pm-12:30am/1:00am I am awake
  12:30am/1:00am-6:30am I am asleep
  I work from 2:30pm-10:30pm

One of those sunrise alarm clocks, going to bed more than 8 hours before it goes off, a neti pot or benadryl so I can breath while sleeping. Blackout shades, and an air filter that makes some soft white noise.
- Sunrise alarm and more than 8 hours before alarm is the best for me
  
  Only problem is my kid sees the light early on and assumes I am already awake. Then he comes and puts a hand on my shoulder while leaning in with the light behind him. Not sure that one will make adulthood. Lol

Go to bed early the two nights before, if it's just a one off thing. If I'm adjusting my schedule I'll take some NyQuil or melatonin to help sleep only the first two nights or so.
- This is my way as well. I would add that I also don’t drink alcohol or eat 2-hours before going to bed. Z-Quil works in lieu of NyQuil.

Try Melatonin and Vitamin D about an hour before bedtime.
- Melatonin is a hormone. Taking it consistently can fuck up your body’s natural production of it. It should be used sparingly.
- Wait, why vitamin D before bed?
  I thought your body produces it in response to daylight, so I always thought that should be taken in the day?
  
  Actually, yeah, that may well be a "me" thing. I shouldn't presume. It really helps me feel more alert in the morning when taken before bed, I've noticed, having tested just Melatonin and the two together repeatedly, but I shouldn't presume everyone would need it. Though, it's Vitamin D, so it probably won't kill you.

There's always going to bed earlier.
- Doesn't work for everyone.
  Some people always go to bed early and wake up early. They complain if they sleep on because it is too far from their natural sleep cycle.
  Some people go to bed late and wake up late and getting up early sucks even if they get the same number of hours of sleep.
  Some people can adjust. Maybe even the majority of people can adjust. Not everyone is able to adjust.

Pay attention to your sleep cycle, so you don’t wake up in the middle of deep sleep. And as others have said, wake up early the day before so it’s easier to fall asleep
- I think I used to use this website to try to figure out when I should go to sleep based on when I needed to wake up. I eventually stopped because I got to where I could figure out 6, 7.5, or 9 hours + 15 minutes on my own (or even 3 or 4.5 hours if I made poor decisions about when I’m going to sleep). It seemed to help.