In order to achieve part of this cracked look I needed to use a crackle glaze. For my first time experimenting with this it was pretty easy to work with. I found out quickly that when working with this stuff, speed is your friend. The glaze has to be painted over very quickly with paint or you can botch the whole thing. When painting over the glaze the cracks appear before your eyes, but don't try to brush back over an area you did already or you'll destroy the cracked look. Smaller or bigger cracks can be made depending on how much glaze and paint you apply.
Here's a close up area of the crackling.