Every part of the art must contribute to the target emotion. Each word, each chord, each melody, each brush stroke, each line, each form must be individually chosen to stand out on its own, yet consistently build toward the overarching emotion. Such delicate, intricate crafting undoubtedly takes time and much energy. Pouring oneself into a piece wholeheartedly isn't an easy task, but it's highly rewarding.
I have to admit, the things I've said are lofty goals indeed. I have most often failed to live up to them (if ever). But don't be discouraged. I encourage you (and myself) to spend more time on your art before you classify it as finished, to carefully construct every detail to your original blueprints, and to never forget that emotion that triggered it all.
Let's show the world what God has endowed us with and blow everything away with creativity and originality. Not us, but Him. Disclaimer: A lot of my thoughts originally came from "The Poetic Principle," an essay by Edgar Allan Poe (at least I think that's where they came from).