Some tips and tricks from Matt James, a designer for 4e.
I can't remember if I put it in the article (I'm so tired right now and should be sleeping), but I wanted to paint a big neon sign around being persistent. The cliche 'If at first you don't succeed, try try again" really applies here. Besides, you will inherently improve.
Oh, and don't forget to keep your queries somewhere. You might have some great ideas that could get lost. Just because they don't get snatched up right away, doesn't mean they won't later on.