Same as the other books of mine plus a couple more: 

1. Please no inappropriate, sexist, racist of hurtful comments. I want this to be a safe zone for everyone.

2. No serious blood or gore, just a bit of blood is fine though. 

3. If you fail to comply with the specific rules of the art contest then you can try again and fix it. 

4. don't get mad if you don't win, there are always more!

I won't be judging it on any specific terms, I will just choose the one that, in my personal opinion, has the most heart and creativity.