Every time I go to either Petco or Petsmart I bring my cat Marley with me.
He is a crowd pleaser since he is a Munchkin cat (midget cat).
So I just put his harness on and a leash, set him in the cart with the stuff and we just walk around and he smells things or sees the fish, etc. Its a good outing. Lol.
It is a plus though to have your kitty leash trained as I do mine, since he was 8weeks old.