How can I lose weight without taking supplements?

I'm 5"7, 18 years of age and I weigh 180 pounds. I want to lose weight by summer time and get to about 165 pounds however I don't have much time for working out as i am studying for exams. I have tried to cut my calorie intake but i am not seeing any results and I was wondering are there any other methods I could try in order to see results without using weight loss supplements?