The BBC's revision guide has excellent resources for regular visits.
This also has an area called SOS Teacher where you can ask a teacher questions.
This has practice examination questions and facts to top up your knowledge. See the posters around school for further details:
Log in instructions:
Centre ID: BR3CP
User ID: Date of birth followed by initial of forename and initial of surname (eg 100992HM).
(Sometimes only works without the 'www.')
School code = "KCSW" username and password.
You have to register for this, but it is free.
Examination boards for past papers and specifications.
Click on qualifications;
Pick your qualification, e.g. GCSE;
Pick your subject, e.g. science double award modular;
Click 'assessment material' for past papers and answers.