Write. You may be a good writer, a bad writer, a successful writer, or an unpublished writer – but write and you are instantly a writer.
Also, while the (Great American) novel seems to be the zenith of every writer’s aspiration, there are other ways to express ideas. As publishing (d)evolves, writers might need to evolve also.
Also also, read your work out loud. I read everything I write out loud (albeit usually just under my breath). So doing allows me to judge balance, cadence, rhythm and style – or, more often than not, the lack thereof.
Also also also, love words. Delight in words. Roll them around your tongue, and escort them gallantly onto the page. Words, like cooking ingredients, should be crisp, fresh, and of delight to the eye and tongue.