Go through your textbook and notes and look for information you feel is relevant. Information could include key terms, facts, explanations of concepts, and parts of diagrams and graphs.
On a blank index card write something that requires an answer on one side of the index card. You may write such things as "What is (key term)" or "Explain (concept)."
Write the answer or sufficient information for the answer on the other side of the index card.
Stack the index cards with the question side facing up as you write them. This way, you can quickly take out your flash cards and study without having to reorganize them. Shuffle the cards if you desire.