Textures and interface

For a huge, free source of textures, check out http://www.cgtextures.com/
Once there, you can find almost any man made or natural texture.

To apply these textures to an object in a more manual way, watch this tutorial about UV mapping: http://www.youtube.com/watch?v=QFiPN4Z_Glg

For those who wish to use Blender on a laptop, watch this:
http://www.youtube.com/watch?v=9XoTZtV8QxA

Blender Short Cuts

Here are some helpful short cuts for you:

Also check out "Blender Guru".
for other tutorials and hotkeys.