I did OCR. None of the textbooks or revision guides were great, so I looked through all and picked the best bits. But really, none of them were especially helpful so it was hard to know what you needed to know and what had been left out of the textbooks/ revision guides.
To have a more specific summary of what you need to learn, print off the specification for your course and make notes under each point. This is the only real way to cover everything. But at A Level, especially for OCR, you're left a lot on your own. The resources really aren't up to scratch (or weren't last year).