The best way to come up with one is to go browse around CSS galleries, use Kuler (http://kuler.adobe.com) or just look at photography. Eventually something will hit you and give you inspiration in what you want, and you just have to take it from there.
I actually meant it tongue in cheek, though it is partially true.
Its partially true though. Most designers I've talked to can't explain how they get from a concept (original inspiration) to the final product completely. For me, things just sort of click, or I'll get weird ideas and just put them into action and they either work or don't.
The sliders will only do so much. Try venturing into the style properties and experiment with the css and once you feel comfortable with that migrate into the templates and tinker, that's where you'll get the better results, tinkering then failing, then failing a little more, then a little more until you ready to grab the monitor and accidentally knock it onto floor and then when you least expect it you'll would have mastered a technique that is both unique and something you'll like. It's about experimenting until you get something you like and then building up from that. Good colour usage goes a long way, styles don't necessarily have to be complex, the simplistic of styles I've seen have been the best visually I've seen but the sliders won't do this alone, there has to be those little touches to the visuals thrown in.