The favored approach to learning in the U.S. these days is to gain an understanding of concepts. For language learning, this works well enough for things that are conceptual in nature, such as grammar. However, a lot of what you have to do along with the concepts is memorize the details. Understanding how simple past works will not bring you to knowing that the past of run is ran.
For my Intermediate level English course in San Francisco, I recommend a totally unexciting, old-fashioned, wholly effective approach to personal memory drill – the 3 X 5 card (sometimes called index cards or file cards). As long as you don’t overuse the approach, it can be very useful, and not overly boring. The key is in doing the work in small doses (more on that in a minute).
It’s really simple. Put the prompt information on one side (if, for example, you are working on irregular verbs, put the base verb on the front of the card). On the other side, put the information you need to learn (in our example, simple past and past participle of the verb you put on the front). I suggest a group of 10 cards. Now drill yourself. Look at the front. Say the word. Now try to remember the information on the back. Say it. Check. If you are right, say it again, and go on. If you are wrong, say the right information, and go on. Go through all 10 cards twice. Then stop. Total time, under 10 minutes. It works even better if you can do it with a partner. If you do this two times a day, you can almost certainly gain mastery of that information in under a week.
There are two approaches to replacing the cards. In both, when you can do the card perfectly 4 times (2 times, 2 days in a row), you set the card aside. You now know this information. If you like to totally complete a task, and have that satisfaction, continue with the same group of cards (fewer all the time) until you have done the last one. Then get a new group of 10. If you like a continuing challenge, keep replacing the ones you have learned with new ones, so that there are always 10 cards in your set. It’s your choice.
These cards aren’t very big, so carry them with you. Waiting for a bus? Go through the cards one time. Your friend is late for your lunch date? Bring out the cards. You get to school really early, and the door is locked? Time to study your cards. If you fill just a few wasted minutes a day with this activity, you will soon find that you know a lot more than your classmates. Don’t tell them your secret. It’s just between us.