That's awesome! By far, my number one concern would be to not skimp on public awareness of your store. Get your name out there, build a repore with customers, specifically list reasons why local is best and what your store has to offer (indirectly list why it is better than what chain stores have to offer), and do it through mediums that have wider audiences such as the local paper. I can not stress how many local stores I see go under when a Petsmart or Petco move in. I am not impressed by either chain on a broad level (and that is coming from working at one of them...can't even tell you which that is how personable they are), and hate not having a local option.
I think having knowlage is powerful in a pet store. And even more important, admit it, when you don't know.
I bought fish from a local pet store. And the owner of store actually sold me 2 sharks and 2 blood parpt fish, for my 10 gallon tank..
I was so happy with my purchase till I got home and called SIL, she was like you got what... (I didn't know anything about fish) So he got this one sale from me, but for now on, I go else where for all my pets needs.. I go to a store, where the young lad, actually will say.. That's not a good idea to buy that..
so not that you need advice, but be truthful.. If you don't know anything about it.. People would rather that, then being lied to for a sale..