Try to be organised, make a timetable with 1 or 2 hours a day of revision. Make sure you try to attend school revision sessions too because they help a bunch. I regret not going to them more when I was in school. Also maybe Skype a friend and revise together because it makes it more interesting, personally I put sticky notes all over my room in the areas I looked the most (e.g. desk, mirror, door), but most importantly don't stress. When you're worried about it work becomes harder and then you become less productive, meaning you aren't doing work and worry more. Just chill, as long as you get English and Maths down you should get accepted at pretty much any college.