>>1 take REALLY good notes, I noticed that I did much better on my tests when I took good notes, so write down what the teacher says not just what she/he writes on the board.
Don't give into peer pressure.
Relationships really complicate things, I went through high school without dating anyone (granted it was a small school).
Keep in mind your future plans, don't stress about them but just slowly come up with a general idea of what you what for the future as you go through high school.
Make to-do lists.
Get enough sleep!!
I hope that this helps :3