What three things a day can I do to better prepare my body for surgery?

Howdy y'all! So I've never had surgery before (other than wisdom teeth) and I was thinking maybe it would be helpful to start preparing my body a bit to put myself in a better position for healing. I have 13 days to do these three things daily (surgery is March 14) but I have no experience, so I wanted to see what y'all would recommend!

The one thing I am confident I'll do is a minimum of 32oz of water a day, but the other two...not so sure. Some options are a certain amount of protein per day, a daily multivitamin or vitamin C supplement, eliminate alcohol, do a half hour walk a day....so many other things I could consider as well, please let me know!

Also, I know three things is not a lot, but I have ADHD so I'm trying to keep it to three so I actually stick to them and do them - three is better than none, and I don't want to overwhelm myself and quit haha. Thanks!