Another good piece of advice that sounds topical as hell but works (almost) flawlessly is exercise. You can try some easy calisthenics routines at home, or you can go jogging, running, cycling — whatever. That way, your brain will release dopamine, which helps with your mood, and you'll also tire your body out, which helps you sleep.
Try to keep a good sleep schedule and avoid junk food — and (I know this might not be popular, given where I'm posting this) try not to play video games for too long, since that can leave you in a low afterward. The higher the rush, the deeper the crash.