Here's a strat that did me well all throughout school. Buy a big pair of black boots. These will be your canvas. Get a black biro, and write all over the boots - formulas, dates, quotes, notes, page numbers, whatever.

In the exam, when you get stuck, simply look at your shoes, and tilt them sideways a bit so that the light catches the slightly reflective biro. The naked eye can't see your notes, but you can. It's never failed me.

Graduated school with straight A's without lifting a finger. Helps that I've got good natural fact recall ability, but the boots have still saved me on many occasions.