As a teacher of study skills, I'd like to draw an analogy from piano practice to study.
Efficiency matters. When I play the piano, I try, of course, to hit all the right notes at the right time. When mistakes occur, they often are the result of an improper fingering used a couple of notes prior to the mistake. Using good fingering minimizes those mistakes. The best fingering is often the pattern that minimizes jumps and turns, making the movements more efficient.
In studying, doing the same thing over and over again won’t profit you much if you are using methods that don’t work. For instance, if you’re a kinesthetic learner, reading something over and over won’t work well—you need to write. If you have to put the tribes of Israel in their proper places on a map, studying the names of the tribal leaders will not be much help on the test. It's important to choose study methods that are not only appropriate for your learning style, but are appropriate for the type of learning you have to do.
“Seat time” matters, too. While efficient practice helps, putting in the effort eventually gets me the results I want. Playing something perfectly one time is fine—but playing it perfectly several times in a row lets me concentrate on the smallest details. Malcolm Gladwell's 10,000 hours-to-be-an-expert rule may not be perfectly true, but it's hard to be an expert if I work only 30 minutes at a time.
When studying, you have to spend enough time to not only learn the material, but to store it properly in long-term memory, and then practice retrieving it. This might involve answering questions, solving problems, or thinking about applications, but retrieval requires time and effort. Lots of students think that when homework is done, study is over. The reality is that homework is just the beginning of the learning process.
Pay attention to how each segment relates to the whole. Good musicianship requires that melodic lines not only have the correct notes played with the correct rhythm, but they also must “say” something. Repeated passages need to be analyzed to see if the general direction is louder or softer, and each phrase must contribute to the overall mood. The difference between a good amateur and a professional musician is not how accurately the notes are played, but how each note is played.
Learning isolated facts may get you good grades on a multiple choice test, but those facts won’t help you become a professional unless you can see how each bit of information fits together. When you learned to read, you may have learned the sound of each letter, but until you could combine those sounds into words and words into sentences that you could understand and discuss, you did not really know how to read. Facts, in and of themselves, are useless; integration and application of those facts into your knowledge of the subject will show that you have truly learned.
Doing boring work often makes exciting work easier. Piano students practice scales, arpeggios, and other exercises over and over again until those skills are automatic. The work is repetitious and dull, and most musicians dread exercise time. I am certainly not fond of it. However, music is made up of lots of scales, arpeggios, and other patterns. When I see a scale I know well in a piece of music, I can just play it; no need to go back and work out the fingering. Learning those little boring bits makes learning new pieces much quicker—I just access whatever pattern I need.
Working pages of algebra problems or laboring over vocabulary words is not fun. However, when you begin to use algebra to solve an interesting problem, or you’re able to read a difficult but interesting book containing those vocabulary words, the drudgery will pay off. Teachers have a hard time answering those “when will I ever use this” questions, but when the background knowledge is there for an exciting project, the boring labor suddenly becomes useful.
Review often. If I practice a song until it’s performance ready, then put it away for a year (or even a month), I will need to relearn it before it’s ready for anyone else to hear. The relearning curve will be much shorter, but it will still be there. Without frequent review, my repertoire will consist only of the last song I learned.
In academia, many students are content to do the current assignment, hand it in, and forget about it. They assume that the material, once learned, will always be accessible. Then the test comes, those students are in for a nasty surprise. While assignments may give you the impetus to learn something the first time, reviewing the information once a week will dramatically cut study time for the next test, improve test performance, and will keep the retrieval path open so that what you’ve learned is ready for use.