Hi, well I've just finished my first year of sixth form (just awaiting results day now arghh). The transition between GCSE and A level is indeed a steep one for some, however I would suggest these tips:
If you have any free periods, make the most of them by doing extra reading around your subject, even when you aren't told to. For example if you are doing history or psychology, read around a theory, concept, do independant research and make your own little portfolio of independant work.
-what worked for me was a summary at the end of each day, where I would go over each of my subjects and briefly summarise what I was supposed to take in over the lesson. (If you keep all this summary, perhaps on revision cards, it means less hard revision towards the exam)
- ive already said this but READ READ READ around your subject, I cannot stress this enough and it's something i did not do enough of admittedly.
-Start your revision early
-Start getting past papers/previous answers early!!!! build up a file
-make sure you are well organised e.g. file for each subject etc depending on what subjects you are doing, make sure you have plenty of highlighters!
Don't waste time, stay focused, use all the help around you, take breaks and generally good luck!!!
If you would like anymore revision tips etc just drop me a message whenever and i will try and help as much as i can!
Good Luck!