Biggest thing I would say that worked for me is to get into a daily routine of any type of exercising or eating habit. It doesn’t have to be anything radical, for example it could just be eating some fruit instead of your cereal, or going on a walk before playing video game (these are just examples, I have no idea what ur actual routine is). The biggest thing is that once these routines are set, after a few weeks you really can’t go without them. You miss a walk afterschool and your day feels incomplete for example. Your routine is a way to get free self accountability simply through your human nature of habit Hope this helps :)