I used to write single sentences as entire posts.
A relative quote that I think is key to remember in any artform and medium is this— “if you have the ability to work with people smarter than you, always try to be the least smartest person in the room and surround yourself with talent, because iron sharpens iron.”
Replace the words “smarter” and “smartest” with your choice (“talented”, “experienced”, etc.) and you will realize what you want to do and achieve it. It took me some time to meet my peers but RPing with them made me absorb their creative philosophies and ideals for the better of my artistic ambitions. I’ve written with minimalists, old school descriptive writers, and everything in-between. Even when I started writing on this site I ended up trying advanced level RPs and after some time in these projects I began to pick up on new word choices, more descriptive text, and imaginative designs; but what really happened was I pushed myself to be better and to meet what my peers were doing.
Find a group, perhaps people you admire (hence the mentor point Ruby mentioned), and have fun.