TIP 1: You will get a timetable for your classes. I would suggest that you write it out 2 more times. Tape one of the timetables onto your locker, and one up in your room, so when you are leaving in the morning, you can have your bag organized so when you get to school, you can straightaway put the books that your not using for this first 3 or 4 periods, in your locker. It would be good to tape one on your locker door, so you can just make sure you have all the books you need, are in your bag ready to go to class, because you dont want to have to be pulling out your timetable every time.
TIP 2: When you get the key for your locker, I suggest you get another two of them cut, just in case you loose one. When you get the key, put it on a key ring. Keep another 1 of them in your pencil case and do not touch it, and keep the other one at home maybe in your room. Keep the one that you have on the key ring in your pockets for easy access.
TIP 3: Set your alarm, and try not to sleep in. OMG! On the first few days, it was so hilarious! I have to go with my friend, and he's so slow to move sometimes, so I end up going into school 5 minutes before the bell goes, and I have to go to my locker and get my bag organized and get all my books. Luckily, I actually made it to class on time though, but im just saying, if you are being constantly late for class, the teachers wont be too impressed. So far, I have never been late for class though, so im very lucky :)
TIP 4: If you bring your phone to school, make sure you set it on silent, because, again, the teachers wont be impressed if your phone goes of in the middle of the lesson. You could also keep your phone in your locker.
So yes, I hope that has helped you organize yourself :) I will hopefully be posting often enough now, if im not laden down with homework! Bye for now though! :)