- Read books on writing. I recommend Grammar Girl's Quick and Dirty Tips For Better Writing and Element of Style. You could also add AP Stylebook.
- Write often. Preferably write for an audience other than you. Start a blog or write a book.
- Evaluate your writing. Don't just write but compare your writing to that of professional/better writers and keep asking yourself what you need to improve on.
- Read a lot of blog posts on how to improve your writing.
- Be bold and creative. Don't give yourself boundaries. Be daring in your writing.