as someone who has 7 years of being a miserable teen under her belt, yes i do haha !
1) carry a journal. make it small or compact, so you can bring it anywhere. whenever something tickles your fancy, write it down in your handy dandy notebook. then , once you have enough snippets and glimpses, see where you can go from there
2) write in all dialogue when you’re at a loss. pull a conversation from 2 people.
3) read read read read READ READ READ!
4) if you write on a word document/laptop etc, print out anything and then read it over, like you would a book. see how it flows. edit.
5) read everything you write out loud. stitch together any odd junctures, smooth out rough edges
6) don’t be afraid to experiment. did something start out a poem and end up as a 20k novella? good. good. go from there !
7) small words are your friends. simplicity will not betray you.