Step 1) Read Strunk & White's Elements of Style.
Step 2) Read Brown and King’s Self-Editing for Fiction Writers: How to Edit Yourself Into Print. Repeat.
Step 3) Write a short story or novel and take it to the critique boards. Get your feelings hurt when people point out all the problems. Cry a little. Try again. Get your feelings hurt again. Try again. And again. And there will still be problems, but maybe not as many, and your skin has gotten thicker. So now you've learned how to take criticism. A lot of people live their entire lives without learning this skill--be proud.
Step 4) Repeat Steps 1 and 2.
Step 5) Keep writing. Keep editing. Develop a style; find your voice. Write more. Edit more. Send your novels to literary agents and publishers. Get form rejection letters. Realize you're not so special. Keep writing. Keep editing. Remember, this is what you like. Don't give up, because you've already succeeded. You are doing what you like.