There are many questions out there about what a writer should do first. The usual advice is this: read. Reading opens minds to numerous possibilities and allows the writer to grow by taking examples from others and converting them into their own style for their own works.
The advice is also given to read heavily in the genre you intend to write in, but also in others you don't. A writer can't know in advance what he or she will take from any given book until the last page is read. An author should have an open mind about everything they read.
Another source of information just waiting to be discovered by an avid reader are blogs. Blogs are often written by those who have the knowledge that's needed by beginning writers. There are so many out there it can seem overwhelming. All that's needed is a quick web search using Google and a writer is likely to find what they're looking for.