I was watching a TV show the other day on chimps in the wild and comparing them to humans. The show was asking the questions what qualities do humans possess that make them human? One might think it is the ability to use tools, but it's not. Chimps use tools. And they can learn language so that's not it either. The answer is: humans care about each other and about their environment, which chimps, or any other animal cannot.
That surprised me because I would have said it is our imagination that makes us human. For me, the imagination and the ability to create something from it is the most human thing, humans do. Personally, I can't imagine (no pun here) a life without my imagination. I used to (and still try to) daydream where I let my mind go where it will. Sometimes I end up in odd places that I like and sometimes I don't. But even my failures, if you can call them that, are saved because I never know what I'll need for a story in the future.
But imagination by itself is not enough to write. It has to be tempered and honed like a muscle. You need experience to draw from and enough command of the language you are using not to embarrass yourself. Reading helps with this more than anything else.
Specifically, you want to read in the genre you plan to write and you want to read the stories in that genre so you know what the masters of the genre have done already. You want to read philosophy for ideas and debate of questions humans have tried to solve for centuries. I also find well-written books on science (physics mostly) help to so you know how the world works and what new discoveries science is unlocking. Lastly, books on history are great because you can learn how people lived in by-gone age.
If I could add one more category of book to read it would be books on writing. I love to read the advice of John Gardner or Ray Bradbury or Stephen King on writing. I review it now and again to keep me fresh.
But you have to write too. And in the early stages it does not matter what you write about. Write about what you have been reading, write about the bad day you've had, write about this one person who pisses you off because she sends unrealizable request by email and you don't have the heart to say no.
Then when you are sick of writing whatever pops into your head, do a little planning. Think of a story line and a few characters. Develop them. Then repeat the process. Share them with others, get feedback, revise, rewrite, and try again.
If you are brave and have no ego, try to have one published. And keep writing and reading.
And above daydream and imagine.