I am completely on the same boat as you, i was getting predicted grade 4s and 5s in my year 10 mocks. My teachers have said that now i have a better chance of gaining 7/8/9s
I have found that flash cards/revision cards work best for science, maths i would advise tutoring and lots of past papers, english watch youtube videos and study the texts ALOT.
If you are doing languages then i would advise learning formal vocabulary. If you are doing history/rs then learn structure and all key dates/references.
ALSO
Ask your teachers what will come up in the december mocks, so you can perfect those areas then move on to other parts of your other subjects. Apart from maths, the entire syllabus is not tested on.
Regards