Regularity in writing is the key. Improvement comes through practice. What can get you writing every day? Making a game of it can help. You set yourself a challenge, and then you rise to the occasion, or not, I suppose.
Poetry, prose, and non fiction all stretch different muscles, and require different kinds of discipline. The writing of one type of writing can inform and educate the others.
There are rules for each, and once you know them you can play with them, and choose not to use them, or play against them, you can create some really interesting things.
I never understood why people write who don’t enjoy it. If you don’t enjoy it – either don’t do it, or change something.