Old habits die hard, but there's Reddiquette which needs to be revived, and some which needs to die.
Many "golden-age" redditors remember a time when downvoting was reserved for hostility, not a different opinion. For the sake of our growing community I would like to implore everyone to be awesome to each other.
However, this place is not Reddit.
We don't measure in bananas here.
We don't need to append "edit: typo" to edited posts and comments.
if you see something which is worthy of a downvote: down vote and move on! Don't engage with it and feed the algorithm/engament machine so other people are exposed to it when sorting by active.
Again, downvote not for disagreement but for content that clearly does not contribute to the discussion. Reason should not be given, as downvoting should be done sparingly and should not require a reason (for most sane human beings).
Be aware when interacting cross-instances. Culture, norms, and rules may differ.
Unless the instance operator is fine with it, limit your self-content sharing and self-promotion.
Remember that most of the fediverse instances are independent and they owe you nothing. The instance operator's decisions are final.
Do not squat names on multiple servers unless it's what you generally have been using.
Cats are still the supreme beings. The fediverse resides on the Internet (assuming that it runs on TCP/IP), so the cat supremacy rule applies.