It depends what you mean by 'tricks' really, doesn't it? :-)

You can do an awful lot with very little if you take your time and think. For example, here's one of the layers from my "Delicate Work" image. The whole image is made from four main layers with another three simple layers to add some subtle lighting effects. Each of the four main layers is coloured using Doodads which is pretty great for this fake 3d stuff. This particular layer has a gradient with only three points on it, so you don't even have to generate really complex gradients to give an impression of 3d.

Just so no one thinks I'm cheating, this layer uses a private formula, but most of the 3d effect comes from the Doodads and gradient combination. I've anti-aliased and sharpened it, and added the SK, but no other pp was involved.

Best wishes,
Simon.