When colouring them in, Do Not Go Over The Lines. You'll really notice it. Also, believe them when they say the colour gets considerably darker.
If the Shrinkles had been mine instead of my eight-year-old daughter's, I would have cut off a bit of edge, tried all of the colouring pencils and baked it, to see how they worked. But that was SERIOUSLY not an option.
Other than that, just follow the instructions. Make sure it's a book you don't care too much about - a phone directory maybe.
Post pictures!