*kiss up to teachers - you'll wind up making more money than them in the future, probably, so why weigh them down? they've got families to - do your homework, be kind, and stay out of classroom drama.
*reach out and test the waters. once you graduate, friendships don't last as long. work on building up relationships, even if it's nerve-wracking.
*do your homework. being late a couple times is fine, and sometimes you'll have to stay awake late to finish a product. write as much as you can - teachers love it. search up ways to formulate your writing and, like i said, write a lot down. even if it's garbage, so long as you add in a bit of colorful language and your own flair, they'll love it. this can be applied to literally any subject - except math, i guess.
*work hard on projects. they're as important as tests.
*study if you need to on tests. i've never studied before and i'm going to need to start now if my sources are correct. i wish i'd learned these habits back in middle and elementary school.
*stay out of drama and mainstream friend groups. they'll either wind up smoking in HS, or worse. trust me - even the smart kids in those groups are getting into some bad stuff.
*drink more water, exercise, yadda yadda yadda. create those habits when you're young.
*join sports, they look good on resumes.
*learn how to write a resume, cook, and other things.
*read more - it'll make you seem more sophisticated and expand your vocabulary.
*tone down your enthusiasm and energy. yes, you are annoying. no, that is not a problem. but when you're my age and still an annoying gremlin, it just makes another batch of insecurities that you need to swallow.
*a lot of the things you will feel will be "just a phase". your brain chemistry is changing, and in order to ride the waves of this without hurting yourself and others, you're going to need to keep this in mind. if you feel like it's necessary, find a local psychologist near you, or a counselor. you will be fine.