Test yourself. Flash cards are effective tools to improve your learning. They help you to memorize facts quickly.
Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Once you've given your cards a good try, put them away. Wait and take them out again before you go to sleep. Remember that sleep consolidates memory. And bear in mind that material that you do not review is easier to forget.