Organization! You now have to keep up with different teachers, different homework, different classes, different requirements!
Stay organized and it will make your year easier. Use those 3-ring notebooks/folders that you have! Keep your class notes all in one section, your homework that you are working on in another section and your tests/quizzes in another section. Do not throw out your notes or your graded/returned homework - it all can be used to study for quizzes and tests.
You may even want to get a separate folder to keep in your 3-ring notebook to hold active homework in (homework you are currently working on).