My “you can’t fail if you do this regularly” formula:
Lift weights. Do some cardio.
Move your body every day.
Eat like an adult.
Mostly whole foods. Keep the junk in check. You already know what a good diet looks like.
Read.
Books (fiction and non fiction). Long form articles. Not just tweets and headlines. Avoid newspapers.
Put something good into your brain.
Write.
Something. Anything. Even if you're not a "writer."
Journaling is a great place to start. Give yourself some time to think on paper. Clarify your ideas. Even 20 minutes goes a long way.
Sleep.
7–8 hours. Go to bed earlier than you think you need to. Everything works better when you’re well rested.
Talk to people in real life (aka an extension of the "touch grass" philosophy). Friends, family, strangers (gasp!). Be open. Be friendly. Don’t live entirely online.
Do these things consistently and it’s honestly hard to not to end up in a good place.
Nothing fancy here either. No elaborate protocols or rituals.