I need help with 3d shading/lighting

[xman84]

How do you guys handle shading in a 3d world? I have a directional light source that shades one side of a tree made of cubes. The remaining 3 sides all get ambient shading only. So the 3d effect is lost when looking at two ambient shaded sides. Am I missing something? Should I be shading the side furthest from the light source even darker?

[ZbuffeR]

Read this :
http://en.wikipedia.org/wiki/Three-point_lighting
Even better, use different light colors for each source.
key = slightly yellow or full white
flood = grey/blueish
backlight = can be orange/red (or even strong blue) for dramatic effects, easily overdone :)