My top tips would to be to; request a lesson plan from your teacher to find out what you will be learning in the next lesson. Then the night before each lesson, correspond to the lesson plan and read lightly / make notes on the topic; by doing so you are effectivly teaching yourself and revising in lessons. Also, don't be dissheartend if you can't fully comprehend the topic yourself prior to the lesson, because, by having previously read about it you will automatically be at an advantage in comparison to class mates.
Devote your entire lesson to learning. Give the teacher your undevided attention. Add any *extras* to notes that you have made the previous night. By having all ready made notes you will be able to concentrate fully on your teachers explaination, clearing up any concerns that you may have.
Use the evenings to get yourself organised. Don't put homeworks / courseworks off, this will only build up and add pressure come exam time, so complete homeworks on the night set and courseworks at a reasonable pace right from the word go. Use evenings without coursework to copy up and clarify notes neatly (come exam time you will appreciate this) and answer practise questions (you don't need to have completed the entire module prior to attempting exam style questions, you can constantly practise questions as you move through the topics). Don't skimp on questions, do as many as you can from past exam papers, text books, or even request additional ones from your teacher.
Be sure to revise for 'end of topic tests' and try your best - this will not only boost your confidence but, also enable you to pinpoint areas which require more focus. Revision should be started early and remain consistant right up untill the exam, a month or two should be plenty as by doing the above you are effectivly revising all year round.