What does it take to work in a pet store?

Hey! I have been applying to pet stores because that is where I have experience. I give a resume, fill out the application very nice and call back to check the application. But the positions get filled and I am getting a little discouraged. I am a graduate of a two year high school animal program with awards for dedication and even came in sixth in state in a competition for small animal care and management. I had a cashier job at a grocery store that I left on good terms because I was beginning my first year of college and wasn't sure I could handle it. I was a member on the FFA and am now on my college equestrian team and do volunteer work for my city zoo. At my previous job and the zoo we were given costumer service training so its not as though I cant deal with customers. That's enough to work at a pet store right? How did you guys get in? and maybe you guys could give some common mistakes as to what people do to not get considered. Thank you so much!