Its all about organisation...
Keep an Excel record of all the exercises in the book (Edexcel), green them off as you do them and write a useful reminder/note next to them.
Do all of the exercises in the book throughout the year, and make use of the mixed exercises, review exercises and past papers for revision closer to the time.
This strategy got me good marks in FP2, FP3 and M3, I only dropped 2 marks in M3 and I'm sure all of the practice in the book helped me loads, and I was panicking for FP3 revision because I left it alone with 20 days to go but managed to get a solid mark while genuinely not being able to do a single question at the beginning.
This is what I did: