Have you ever kicked yourself after an exam and said, ``I knew how to do all that." But somehow when confronted with the problems on the exam, you took square roots when you should have squared and used degrees when you should have used radians. What can you do to avoid having this happen any more?
Learning math is a lot more like learning a language than most students realize. When you learn a language, you often feel good after you have learned a few key phrases like, ``Oú est la toilette?" Then off you go to France, confident that you are going to walk on French water. But after a couple of weeks of wandering around Paris, where everyone else is eating delicious pastries and gawking at very old paintings, and all you can ask for is the nearest latrine, you realize that perhaps a bit more practice in the language would have been worthwhile.
Same with math. Understanding the broad outline isn't good enough. You have to be fluent, conversant to such a depth that you just automatically know what to do. It takes no thought process on your part. It becomes innate.
Of course, in becoming fluent, you want to study the important parts first, namely what will be on the exam.