This is a message to all those who are finding it hard to actually sit down and revise.
Go on your phone/iPod and download on the app/play store "Brain waves".
I had a different problem and found it for something else, but have since found it useful for revision. you take a decent set of headphones, put some music on and open the app to BETA waves.
there are many other ways of doing this but I found that this is the most effective and useful.