>>1 You waste a lot more time than you think, that's all the advice I can give. There's a lot more spare time you aren't doing anything than you realize. For me, I basically just work if I have work. I don't do anything else. I take breaks every hour for 5 minutes, like right now. I don't take larger breaks than that if I'm not ahead.
I don't go to be some nights at all working, so I get that. that was due to bad planning on my part, though. Also, realize you don't necessarily have to hand everything in. Losing some marks is okay as long as you get the big stuff done. If you ever go to University, this is very, very key. You won't be able to do all the work and do everything else you want.
That's my 2 cents. Good luck! Remember most people are in the same boat as you, myself included!