Have to echo the words above, buy the confuser!
I've done all the PPL exams and if you can attaing high 80's and 90's in the confuser you should be up to the standard for the exams.
However, make sure you read all the stuff, its not there for no reason. In terms of actually how to revise, I read the books and highlighted the key points in each section, I copied these poitns into a revision notebook and then sat practice papers. Anything I got wrong in the practice papers I re-read, and it worked.
The PPL Confuser is a great aid, and AFE now do an Air Law questions and answer similar to the confuser, sugest you buy it, however their thick book of questions and answers is full of wrong answers so I dopn't personally recommend it!
Good luck and happy flying,
Rusty.