I think personally it is
VERY VERY important to get motivated first of all. Try to get inspired by simple little things (in life). Things that I do to get motivated:
1. Print out quotes: Life quotes, Student quotes, Funny quotes, Love quotes YOU NaME it and stick it on ur bedroom wall/toilet (make sure it doesn't get wet) make it ur wallpaper in iphone/laptop
2. Listen to relaxing music while working (by ur favourite artists- create a playlist for study)
3. Try thinking positively and believe in urself , if ur a girl (which Im not sure of sorry) compliment urself, look in the mirror (but don't get distracted n start taking selfies)
4. Think of why u need to get these A's or higher--- to make yourself and ur family proud of you, to show that you are better than your filthy enemies, to get into a specific uni....
5. EAT while you study (crisps, lollies, icecream... you can create a food playlist, again if ur a girl you might have weight concerns then I dunno eat salads or bananas)
6. Reward yourself for every page, chapter you study. But build it up slowly as u go..
Good Luck