Easter is a great time to revise, you have the rest of this week and next week to start or continue revising.
First, I highly recommend to make a revision timetable. I made one for my GCSEs and I am still using them even in my last year of A Levels. It doesn't have to be too complex; I just printed out a calendar for the days up until my last exam. On each day I wrote what subject I wanted to revise, and what topics to revise and whether I would do a past paper. I also prioritised the subjects or topics which I was weaker at, and would not stop until I totally understood or memorised the topic. This really helped as each day I wasn't having to waste time deciding which subject to revise.
Secondly, look at past papers. Examiners love to throw some topics in each paper every year, so you can make sure you absolutely understand it and will be prepared for it, for example factorizing polynominals in GCSE Maths. These will also help you prepare your timings better by practicing papers.
Finally look at Examiners Reports. These are documents on the exam boards websites which say how well people did on average for a particular year. These can be helpful as they show what the examiners are looking for, what they don't want to see and the common mistakes people make.
Hope this helps, it definately did for me - 3A*s and 8As at GCSE