The most important advice I can give is that students must get hold of exam past papers and practise these past papers under exam conditions - i.e. with a time limit.
Secondly, it is a good idea to spend around 30 minutes at home every day to go through the work which has already been done that day at school. That will consolidate it in your memory. Mathematics is a very large subject area, and without revising the work daily you won't be able to remember what you have learnt in class.
