I'd have to say--and I think most pixelers would agree with me--that Paint is really the best program for pixeling, hands down. I don't do nearly as much as I used to, but I really only used Photoshop for palette making.

And yeah, as with all media, practice is vital! Contrast is very important, to make colors and shading pop, visually. Sometimes you actually use very little of a base color and more shading and higlighting to allude to color.