The Best Kinds of Drills, Quizzes and Exercises

Don't do drills, quizzes and tests unless you're told to at school. The worst kind of drill is when you are quizzed on random lists of vocabulary or rules of grammar not related to specific content that you are listening to or reading. So again, my rules are do stuff that's easy, not too many at a time, connect it with content you're interested in - let that be 10, 15, 20% of your learning activity.