The most important thing you can do if you want to write is to READ. Read endlessly and continuously. Especially read things in the areas where you want to write, but don't limit yourself; anything and everything you read can help round out a character or make a scene more interesting or real. As an example: Christina Amies (hero of PsiFinder) constantly refers to her background in history. Brian's background in history makes that come alive; because he can talk history, so can Christina!