"To get the right word in the right place is a rare achievement. To condense the diffused light of a page of thought into the luminous flash of a single sentence, is worthy to rank as a prize composition just by itself. Anybody can have ideas---the difficulty is to express them without squandering a quire of paper on an idea that ought to be reduced to one glittering paragraph." --Mark Twain
People seem fascinated by where writers get their ideas. The idea is the easy part. A good idea is a little harder. (Good idea = marketable, interesting, and sufficient to sustain a whole book worth of conflict.) But still... having an idea is not a problem. Trust me.
Putting it perfectly on the page... thats the tough part.