Find & read good self-help type stuff (relevant books by psychologists, Less Wrong posts, Sebastian Marshall, Getting Things Done, etc.) and invent/experiment with your own techniques in a systematic way. Do Tiny Habits. Start meditating. Watch & apply this video. Keep a log of all the failure modes you run in to and catalogue strategies for overcoming each of them. Read about habit formation. Brainstorm & collect habits that would be useful to have and pair them with habit formation techniques. Try lots of techniques and reflect about why things are or are not working.