I would say for writing you need P.E.C. : Passion, Experience, and Creativity.
Passion:
The story needs to be spiced with passion or else it will be boring dribble. Oh, the imagery and language may be superb, but passion is what makes a bland story spicy!
Experience:
How easy is this! Write about what you know and see. If you ask any writer you will know they write about things around them and things that they (had) know(n).
Creativity:
Let your imagination soar. Don't set limits. Remember, every writer writes more then one copy. Your rough draft should be full of whatever your mind comes up with; then, after much review, you shave away the parts that aren't really needed (though this depends on how many pages you are going to be allowed and what the publishers think... et cetera).
Well, those are just my tips.