For high school: your body will really want to go to sleep at 2 am every morning, but don't. Go to bed at a regular time. You might not like it at night, but in the morning your body will love you.
For college: Don't cheat. It might be super tempting, but if you're caught even once, the consequences are so much worse than in high school. Plus you're setting yourself up for failure in the future. Do you really wanna be the guy who cheated their way through college only to end up with functionally zero experience in a real-world scenario where you have to apply what the job thought you learned? Hell, most jobs will probably see right through you and deny you on the spot.
Also whatever your brilliant-ass cheating scheme is, your TA has probably seen it 27 times already.
Also that thing where you go mess up the headers in an empty or irrelevant file and pretend your homework got corrupted to buy yourself an extra day was invented pretty much at the same time as electronic homework submission.