I know of many different ways to study, some that I have come up with myself and others that teachers have shown my class throughout the years. The first thing I think you should consider is what type of style you learn best in. Some people learn better by reading, pictures, videos, experiments, listening, etc. Knowing how you learn best will help you when you study. So, here are some ways that I like to study/review material.

1) Notes - Notes are really helpful for me. Notes force me to look at the material and read it. Then, I am able to organize it and write it in my own words. One of my teachers have said that by writing things in your own words, you are more likely to remember it, rather than a lengthy, pedantic textbook information. Some people also like to color coordinate their notes. Writiing in different colored pens can help you organize the vocabulary words, steps to a process, main ideas and details.

2) Fortune Tellers/Cootie Catchers or Whatever You Call Them - One of my teachers recently showed my class this way of studying. First, you make an orgami fortune teller. They are really simple to make, and there are plenty of resources out there to help you figure out how to make them. Then, on the outside flaps, you can write random words related to the subject you are studying. On the inside-outside flaps, you write either vocabulary words or math problems. On the inside flaps, you write the definition or answer. It's a really fun way to study and you can play it with a friend or alone.

3) A Makeshift Whiteboard - Another way I like to study things is by using one of those clear, plastic binder dividers and some whiteboard markers. Since the binder divider is clear, you are able to slip worksheets or pictures inside and then write on the binder divider without marking up the page. This is especially useful for when you want to do things multiple times and you don't want to waste paper. For example, my science class is studying cells right now, and we need to know the different parts of the cell and their functions. I am able to slip in a picture of a cell from a worksheet my teacher gave us and I can practice identifying the parts of the cell.

4) Teaching - Another good way to remember information is to teach it yourself! Sometimes, if you are trying to figure out how to do a certain type of math problem, it helps to try to teach it to someone else or an imaginary person. Also try to simplfy things so that, let's say, a first grader could understand it. Doing that helps you remember what to do.

5) Note Cards - Note cards are easy to take with you on the go. They are especially useful for vocabulary.

6) Quiz Yourself - Quizzing yourself can mean many things. You can literally create a quiz for yourself, or you can ask a parent to orally ask you questions based on what you are studying. Sometimes books will have an online website where they have practice quizzes with instant results, review games and animated pictures to help you understand the concepts you are studying.

That's all I have. I hope this helps! 

The thing that works best for me is highlighting important things, and then re-writing them. Something about highlighters just makes it that much easier...

Also, reread all the chapters, papers, whatever, even what seems unimportant, but only really pay attention to the important parts. So, listen to music, and when you read something you remember the teacher mentioning, highlight or underline it.

You can take anything you've highlighted, underlined, or re-written and make a contest out of it with your friends. I do this with my friend, and we give one point for each question and have my sister ask the questions. We always end up acing our tests that way!