^ What SupR said was pretty spot on.
If you have to finish off notes for one particular module (E.G. Business Studies you just need to finish off Human Resource Strategies) you can use the time now to finalise, as it will only take a few hours maximum. But if you don't have any, get someone's notes online in the resource section and try to understand the content. Use them while you are doing past papers to see where your real strengths and weaknesses are.
Also do past papers and have them marked by your teachers, this is critical for subjects such as English, Legal, Modern, Ancient, basically any essay subject!
For Mathematics you can go to the answers section and see where you went well and went poorly in, so you don't have to ask teachers to mark. However, if you are struggling with a particular topic in Maths, ask your teacher for guidance and assistance so you can consolidate your understanding.