The single best way for you to improve your writing is to, well, keep writing. Practice may not necessarily make perfect, but it can help to develop those skills and improve them. Speaking for myself, I write every day for several hours a day. I have a couple longer posts that I do from time to time, but many of them are 500 words or less. I have a machine-gun style of writing for those clients (as well as on this blog). As a result of all this work, I’ve been called a pro blogger. Keep writing, daily if possible. It is only through continued practice that you will improve.