Probably the most important thing to them will be your people skills. Like working in a shop, teaching dancing requires that you deal with people of all types. In other words, try to show them that you are a people person.
Show your enthusiasm towards this opportunity. Employers always want people who show enthusiasm towards their work. It also means that you will likely learn faster because you are willing to put in extra effort.
Any formal dance training (ballet, jazz, folk etc.) is an asset. if you don't have a dance background, having a background in other sports or music may also be an asset. They show that you have some body coordination or can keep time to music.
good luck,
Blair