Traditionally, this is done with index cards, but you can also download computer programs that cut down on space and the cost of index cards. You can also just use a regular piece of paper folded (vertically) in half. Put the questions on the side you can see when the paper is folded; unfold it to see the answers inside. Keep quizzing yourself until you get all the answers right reliably. Remember: "Repetition is the mother of skill.