Buy a binder to store your notes, homework, and tests/quizzes in it. To distinguish the difference between each class, purchase tabs or make some of your own. Another option is to purchase folders to either replace the binder or assist it.
Buy a pencil case and put all your writing utensils in there. Be sure you always have an extra pencil in there in case something happens to the pencil you're using. If you prefer mechanical pencils, make sure you have extra lead in the pencil case as well.
In case you have no access to a pencil sharpener in the classroom, bring your own small one. The kind that catches the shavings is recommended, and make sure it doesn't make too much noise! To be prepared for math, it is recommended you slip a small calculator in the pencil case as well. If your pencil case is big enough, put a ruler in as well.
Buy a planner or an agenda to make note of the due dates of assignments, tests, and big projects. That way, when you arrive at home in the evening, you will be able to organize your homework schedule and figure out which assignment is due first, and when you should work on it. Good prioritizing is necessary in this area.
Make sure your locker is clean and organized. Keep it free of random papers - keep all papers in your binder or folder(s) - and do not clutter it with unnecessary decorations, as they are pointless and you'll have to take them down at the end of the year.
It is recommended you stack your books in your locker in the order of your classes. That way, you can easily grab your book from the top stack, and later slip it underneath the pile for tomorrow!
Dress appropriate and nicely, as it shows respect. Avoid wearing clothes that are too small or too big. If you have a uniform, wear it neatly, tucking in your shirt and making