Writers write because they have something to say. But to have something to say, one should read and be voracious about it.
It is through reading, amongst other ways, that an aspiring writer learns and picks up new ideas, and becomes inspired (hopefully) to gain more knowledge.
Read a wide variety of materials. From literary books to popular fiction; from high-brow journals to mainstream broadsheet to the less-serious tabloids. Read magazines that may interest you; scour the blogosphere for topics that may or may not pique your curiosity.
Read graphic novels.
Read brochures and adverts, even those on wallscapes or billboards.
Read avidly and stash the nuggets of new knowledge or data you have learned from what you have read.
This stash in your memory bank will serve you well when you eventually dip your toes into the realm of creative writing.