The best way to revise is firstly to do practice papers/questions, to find out where your weaknesses are (dont revises for them and do them in exam conditions etc)
Next you should find out what type of learner you are and what conditions are best for you to learn in, there are probably tests online but it's quite easy to figure out, for example, I learn best using colour and turning my notes into mindmaps, and I prefer to work where it is silent, however others prefer more loud environments, so listening to music is a good option, and some like to record themselves saying their notes and listening to them.
Only revise the things you need to know and don't already, so you don't waste any valuable time, and make sure to have revision breaks - its difficult to concentrate for a few hours in one go - do half an hour, then have a 5 minute break, then return to your revision.
I hope this helps!