Repeating is a superb study technique.
Bring out your memories again and again.
Try to remember as much as possible with as little help as possible.
Without repetition, the memory paths can disappear.
To retell it you learned, in your own words, is an effective method of repetition.
You must first understand what you have learned before you can retell it in your own words.
If you discuss what you have learned with someone, the chances are even greater that you will remember the knowledge much later.