I'm looking for a book full of practice exercises. I find that, while my vocabulary is getting better and my knowledge of grammar improving, it would really help to do more exercises and compare my understand to reality. The only thing I can find is this? Is there anything else?
Try Grimm Grammar
This is an excellent ressource for german grammar and suitable for nearly every level of knowledge.
There is a good resource, around 30 exercises that are like games to test yourself at www.germanexercises.eu
I've done all of them :)