Qualifications
A good salesman can sell anything. He is a problem solver.
You need to be quick on your feet and adaptable. You need to find something to relate to in everyone you meet, even if it's as small as liking the same kind of socks or wearing loafers.
You must be able to build value in a purchase, upsell the warranty or the more expensive wood that will last longer.
You'll have to stand on your feet all day. Sometimes you'll have a lot of customers to deal with and it will be hectic. Other times you could be bored silly. You need to go with the flow.
Usually retail stores want a high school graduate and may even prefer a college graduate, but unless you're thinking of expanding to a managerial job at the place, it doesn't much matter. This could even be a part-time job while you're going to college to get your degree or a nice summer or after-school job.