There are so many effective ways you can prepare for A Levels such as:
Read books around the subject
Go through first/second chapter of new course To give you a head art and make the transition easier.
Reflect on your previous exams/revision methods and think about successes and ways you can build upon your KS4 successes as well as ways to improve revision methods.
Why not check out the 10 things to do to prepare for your A Levels?