How to revise (for A level biology)

An updated, and I think more clear, guide to what good, effective revision is in biology. I discuss: 1. what effective revision actually is 2. what you might be doing that I wouldn't count as revision 3. what kind of targets you have to set to make revision work better 4. finally, what resources are best for revision hope you find it useful, and I would be interested to know the student perspective on this, in the comments below, especially if there are follow-up questions based on this theme.