Write poetry. Write things that rhyme. Write things that don't. Use a specific poetic form. Or not. Describe things in the most intense forms of imagery there is. Overload on your figurative language until it's on the brink of not making sense, teetering on the edge of that cliff between sanity and insanity. Read it over and over, and question your choice of every word, every syllable, because when it's done, you'll feel better.
Write things that don't make sense. Confuse your readers. Confuse yourself. Let out all your emotions. Write those things that you would never say aloud, write those things that make you groan in disgust or embarrassment, write those things that make you end your sentence in "akljdzsfjlaiuymxs I'M DEAD".
Write about things that don't make sense to you. Social cliques. Sports. Things that are around but you don't understand why they are. Why does the world seem so big? Why is it so limited? Why do I matter? I'm just one tiny human being in one tiny house in one tiny city in one tiny country in one tiny continent in one tiny world in one tiny solar system in one tiny galaxy in the huge universe that is still growing, bigger and larger and bigger and larger.
Write to torture yourself. Write about your fantasies and the things that you just WISH that you could have, but you know are impossible. Write about what you think the future might be. Write about how the world could end one day, and why people like Nostradamus can predict the ending of the world to one exact year - 3797.
Write to express your feelings. Write just to reread what you've written in five years, because in those few years you may well be more mature, or in a better situation, or just needing a laugh from someone who doesn't exist anymore, someone who you were five years ago.
Write in a bullet journal. If you can't form complete sentences then put it in bullets, doodle things to go with it. Not every journal entry has to feel like a story. Not every story has to be written down. Some can be just listed, in bullets.
Write, then screw up your format. write in all lowercase letters because it's been a long day. WRITE IN ALL CAPITAL LETTERS BECAUSE YOU HAVE A SCREAM WAITING TO COME OUT, AND NOT IN YOUR PILLOW. Write normally because it's a normal poem, but no poems are normal, for they are all unique. Type it all up because you've run out of paper, or because you want it to look professional. Center it. Align it to the left, or right. Or make it in a zig-zag pattern.
Write because you're inspired. Write because you don't have anything better to do. Write to finally take your big ideas out of small boxes. Write to be rebellious. Write because you're vulnerable. Write just because.
I can't wait to read what you write.