Don't forget to smile and show that you have personality. Think about what they will want in an employee:
1. Reliability
2. Commitment
3. Excellent Customer Service
4. Self-motivation
5. Ability to help them sell more
6. Easy to manage
7. Gets along with others
8. WANTS to work and is not just marking time.
9. Follows instructions
Don't get too personal, but be warm....you do that with your body language, eye contact, a warm smile and firm handshake.
As previously advised, practice tell them what you can do that will help them. You want to let them know you are a team play who is flexible and someone they can count on to be there and be at work while you are there. You want them to know that you like people and animals.
There's nothing wrong with telling them that THIS job, in particular, is one you really want and that you're a bit nervous because it means so much to you. Don't belabor the point, but admitting you are nervous in a short statement isn't a bad thing.
Good luck!! Let your confidence in yourself overcome your nerves. You know this is a great job for you! Use that confidence to your advantage. When you go there, remember that you know your animals!
We'll all rooting for you!!