How to shed at least 8 pounds or more?

okay well im not fat but im just an average looking gal but i have a little fat i just want to lose and just tone up my body. what do you suggest i do because i try to eat healthy, work out at least 4 times a week or more and im trying to lose weight but i don't know if my sleeping has anything to do with it me trying to lose the weight. Sometimes im up ALL night literally trying to finish my homework or try to study for tests and the next day i have to wake up at 7 and i end up with 5 hours of sleep or less!!! what do you people suggest i do!? should i just keep trying and wait until summer to shed the weight so i can just focus on losing the weight during summer or do you think i can still mange to do it while being in school.....hmmmm idk.