I track all of my "I should do this daily or almost daily" tasks/habits. (Review TODO lists, schedule things for tomorrow, chores)

• How long I read for.
• How many personal tasks I completed that aren't considered chores.
• How many commits I made on my code.
• If I am studying something, how many hours I spent studying and the exercises completed (the latter bit isn't of too much use, other than it being >0)
• Which supplements did I take.
• A rough sketch of what I ate (basically, the food items and rough macro-nutrient quantities)
• If I exercised then I track almost every detail. When/What/Weight lifted/Sets.

I will also occasionally record what my "mental clarity" feels like on a scale from 1 - 5. I don't yet do this often enough for it to be worthwhile, and I may just stop altogether unless I figure out a useful system.

The best thing I have found for my personal habit formation is https://chains.cc/ but there are a lot of "riffs" on this idea out there. I have one desktop on my computer dedicated to tracking all of the things important to me (chains, calendar, TODO lists, long-term goals). I have Google Calendar "event" that creates a popup on this desktop every day at 5:00am, so that ensures it is the first thing I look at.