Just a quick tutorial. I usually use old guides, magazines and other things; the important thing is that they should have a spine. You can use the words written on spines or use nice words from inside the book/magazine. This method usually gives you some texture on the outer edge of the book; this is good if you're looking for a magazine, or a photo book effect, but otherwise you can just paint the edge white, and this will also help to keep the book together, since they often tend to stay open.
