2. Unwrapping in Practice
If you plan on putting photo sourced textures on your models, your first step will be to unwrap your model either using the UVW Map or UVW Unwrap modifiers. The UVW Map modifier works best with primitive or basic shapes (box, sphere, cylinder, etc.) and photo textures that are tile-able. Meaning, the photo textures are repeatable and do not show any seams. It's best to think of the UVW Map modifier as a quick and dirty way of unwrapping your objects. This modifier will work for some but not all objects, especially those that require a very customized texture. In those instances, the UVW Unwrap modifier is best because of it's ability to add a lot of texture detail to 3d objects with fine control over where that detail goes.
UVW Map Modifier Overview (for Basic and Primitive Shapes)
UVW Unwrap Modifier (for Custom Textures)
Helpful tips for using UVW Unwrap Modifier
Tips for using UVW Unwrap to unwrap a face