Try to understand the basic relations between the principal points
of your subjects, create connections, master the important questions, and (really) make sure you know all of these things after studying.
If you have the time then, star working on the details, but remember, first of all, try to focus on the big ideas that are the base of your subject.
Once you've mastered them, the rest will be much easier!
If you are easily distracted, and keep thinking of something else, like TV or something, try to create a reward system: plan your study into parts, and then, for each part you have cleared you give yourself a reward.
Just Remember your brain needs COMPLETE Rest. I covered in earlier post , what is complete rest.
But it is important that you STICK TO THE RULES! Half-hour and nothing more! Or else everything you've done will become nothing!
Oh, and before going to sleep, do anything to keep your head cool, to distract yourself, so you're not worried and your brain isn't focused on studying, so you can get some good sleep.