A product with great engineering will only get you half way there. The other half is great design. I’ve been playing around a lot lately with graphic design, color palettes, gradients, and text effects using Mac apps like Gimp, Seashore, and Inkscape.
A great way to learn a new skill is to look at examples. A nice website I just stumbled on is called Dribbble. It’s a great place to see design examples from some talented designers.
From their website: “Dribbble is show and tell for designers. Players share shot - small screenshots of the designs and applications they are working on”.