What has been said, it really depends on what you want out of it. But here are some "rules" that you can propose and maybe go off from to think of more things:
- Always collared and leashed
- Have to walk on all fours and sit on the ground
- No talking, only noises and gestures appropriate for an animal
- No clothes, or only a specific outfit
- Beg for food and petting
- Regular "walkies"
- Training (obedience and tricks)
It always depends on your kinks and what you enjoy more. Training is usually more enjoyable with a uppity pet, going for walks is probably more for the exhibitionists etc.