The only person who has the ability to teach you how to improve your writing skills is yourself. Only you are qaulified to take the most appropriate steps toward improvement, no one else can really tell you how.
However, there is always one vital step that all writers should take in order to progress further and build upon more skills for their craft. Reading is wonderful and a great way to pick up on new words and styles.
Even if you are not much of a reader or you absolutely cannot stand the thought of picking up a novel of any shape or form, scanning newspaper articles or even online newsletters is a good idea to flex those creative muscles. As a writer, it is always necessary to learn every single day. We are made to adjust and adapt along our writing journeys, so there is always, without a doubt, something new to find.