The Integral Maths website has some excellent revision tools including notes and examples on different topics, flash files with many practise questions, worked solutions of questions from the text book and multiple choice tests to test your understanding.
You are expected to go on this site regularly as part of your independent study.
Mymaths is a useful website to brush up on GCSE knowledge and to use for extra practise.
It also has all A-Level topics - go through the lessons on the site to consolidate your learning in class and try the homework to test your understanding.
Remember to login so your teacher can see your independent work.
Mathscards mobile is a free mobile download with useful formulae that you need to commit to memory.
Download the A-level cards and you can flick through them any time on your phone.