One technique I discovered early on is ambient lighting using a texture cube. A texture cube is a texture made up of 6 images, one for each side of a cube, that should smoothly fit together to make a complete panorama.

Rather than use this texture cube just as a skybox, I use it to sample ambient lighting.

Texturecube ambient lighting

The other nice thing about using a texture cube is you can quickly blend them together to subtly alter the lighting or smoothly transition from sunset to night.

This technique works well in conjunction with an Ambient Occlusion layer in your shader, as you don’t have to have overwhelming fixed lighting when baking your model’s textures out.