Personally I hate minimalistic designs which is what everything seems to be these days - especially eco-stuff. I'd try something with 2 or 3 bright colors in a "busy" pattern with sharp edges. Kind of like a mountain dew bottle - or the UK flag (thanks above poster
You'd probably have to modify that for fashion and textile items, but for the love of Bob do not come up with something minimalistic. Whenever I see a design like that on a product I immediately want to stay far away from it.