As an autistic person how do you stay motivated (more specifically doing long tasks)?

Mostly separating them in smaller tasks that I can see as making progress.

That's the only thing that helps me with them

I seem to like tasks to be finished, because if a task is finished, then I don't have to do it. Once I start doing something, I find myself motivated enough to get to the end of it and put it behind me.

It's the starting a task part that I have trouble with. Sometimes I'm able to start something by brute force of will, and just doing "the very first thing" without thinking about anything that comes after. "I'm just going to do the thing that starts this task," and once I'm in the task, it's not nearly as hard for me to work through all its steps and make it finished, and by extension, gone.

Once I start doing something, I find myself motivated enough to get to the end of it and put it behind me.
It's the starting a task part that I have trouble with.
I have so much trouble starting that if I do get rolling, I have to finish. Otherwise, I may not start again for a good long while, if ever. Which of course adds to the stress.
On the other end of that, I find very little satisfaction in "finishing" anything. The specter of the other things yet undone is always right there, ready to pounce the moment I try to rest.
It's an exhausting dance.
- I've had some success in also reminding myself that it's okay for me to feel good about accomplishing even a simple thing. Did my wife have to remind me several times to submit my expenses to work before I finally did it? Yes. Did I do it? Also yes.
- This can be dangerous, but sometimes I will force myself to stop short of reaching a good stopping point. Like, say you have to put up panelling, and 5 sections will cover a wall. Put up 4 panels and stop for the day. That 5th panel not being in place will drive you mad until you dive back into the project.
  This will sometimes backfire, and I do have years-old half-finished projects that I've wandered away from

Routine. I do the same thing at the same time each day with special days where I do the more rare tasks that aren't daily. It's great for executive dysfunction because I don't even have to think about it, when it's that time I do that thing. It took a while to get here and of course there are bad times where I'm off my routine, but I started slow doing a little bit each day and built to this. It's crazy to see where I'm at with a lot of difficult tasks vs. where I started and that progress only helps to reinforce the routine.

I am a bit jealous of your ability to build it up like that. Happy for you, but frustrated for myself. The ADHD parts of my brain scream bloody murder any time a routine starts to set in. It's like, I know I need some sort of structure. But even for things I want to do, the internal pushback against Time To Do The Thing is almost primal. It's a pain in the ass, and it's only gotten worse with age (and trauma). The executive dysfunction is all knotted up with the anxiety, depression, stress, OCD tendencies, and unresolved trauma, woven through with recently-diagnosed autism that's been there my whole life (yay hindsight) and a rigid mask that I built myself around since childhood. Trying to tease out a dangling thread just pulls the whole knot tighter.
- Sorry to hear about that it sounds very hard.
  It definitely wasn't as easy as it might have sounded and I was very lucky to have been given a second chance where I was able to focus on these things.
  But one of the biggest lessons I have learned along the way is that those people who say give it 100% are not for me. The only way I can get anywhere is to give it 5-10% today and then just keep trying to do 5-10% everyday. Eventually that 5-10% becomes 20, 30, etc. until I get in a nice rhythm whereas if I started by pushing myself to 100% on day one I would never do anything on day two. Not trying to say it's what's right for everyone or that it would work for you, but I wish you the best, it's a hard path.

Tons of caffeine. If I have energy I have motivation, fake energy works like real energy.

Ahhhg, I wish. If I have too much caffeine during the day I'll spend all night remembering embarrassing moments instead of sleeping. >.>

Methylphenidate.

I mostly have issues starting a task but once I get going I can keep going for a while as long as I have music and am not interrupted.

Pretty much the same for me, but videos included in the mix too.

What helps me is listening to music with repeating sounds. It paces me and allows me to keep doing things for a longer period of time.

I essentially gaslight myself into thinking I'm finding the activity fun. I also find that music helps, as does finding a rhythm in the activity.

Of course, I'm generally fine with long tasks anyway, so your mileage may vary.

I don't. I was lucky to have a career that was Autistic-friendly. ATC if you're wondering.

Prescribed wording, firm rules, absolute authority, no personal interaction.

I would love to work at a place like that. :I
All I need are absolute prompts on what to do.

I've started using a stopwatch, and my aim is not to complete the task, but just to spend time on that task and nothing else. This does 2 things: 1) just the fact I'm on the tasks moved me forward more than not being on the task. 2) as its counts up, not down, I am just interested in increasing the number, so every 30 seconds or minute or 10 extra that I do makes the number bigger and the dopamine higher.

I combine this with a habit tracker (literally called habits on android store) so I can try and beat my last high score etc.

I don't set myself any targets etc that would cause me to feel shame (and then procrastinate due to that shame), so it lowers the barrier of startinf sufficiently low so that I can get on. And then the flow starts to kick in and we're off...

I don't do long tasks in one burst, but in like 15-25 minute increments depending on my mood.

Try to research the task, and why there should be importance placed upon said task (whether it's the end result or something else).

Most things have some importance to them, it's just that I don't often take notice of it until it's pointed out to me - so I try to make it so I can point it out myself, if that makes sense.

To Do lists coupled with the above helps as well, though to each their own.

At work we have "daily" short meetings.
I can share partial results of my long running task.
Somehow it helps, I usually get praise from my boss.

I take breaks until I'm ready to start. Risky but work for me

Modafinil, along with redundant calendar, alarm, and Alexa alarms and reminders.

not possible at all.

ritalin works though

audiobooks/podcasts. without them, i can't focus on what I'm doing. but when I'm listening, I am able to settle down and dig into whatever I'm doing much easier. like others are saying, actually getting started is the hardest part

ephedrine