There is a misconception among some students that English learning is iust a matter of learning some grammar rules and memorizing some new words. So the most important thing for them is to read a grammar book over and over again and to recite some new words from a vocabulary book or from a word list. However, the fact is that acquiring a language is about learning a skill, rather than memorizing a body of information. That is, you must not only understand the ideas and concepts, and have information at hand, but also make yourself get used to using that information in listening, speaking, reading, and writing. You need, then, not only to memorize, but also to practice! Here are a few suggestions on effective study techniques.
First, make your mouth and hand do what your mind is learning, i.e. produce language. Read aloud. Listen to tapes. Study with a friend, thus involving yourself in speaking and listening. Try to write sentences or a short paragraph using the skills you have practiced orally. Second, study daily. You can't get by in a language course by cramming at the last minute. You may be able to learn vocabulary that way, but you can't let your mouth speak them in conversation or your hand write them in sentences. Third, go back and review "old" topics and vocabulary. Language learning is cumulative. You learn new skills on the basis of old ones. The more you go over familiar information and skills, the better you will be able to absorb new ones. Finally, don't be afraid to make mistakes. Self-consciousness can be a great obstacle to learning a language. Part of the reason small children readily acquire language is that they are not afraid of making mistakes.