Their onsite SEO is pretty well done already with good page titles and navigation structure. They also have a decent amount of inlinks. I don't really think SEO is their problem. If I were them I would recommend working more from a marketing standpoint. They need to get on the phone with places like dance studios and dance competitions and see who they can:
1. Get their catalogs posted at these locations
2. Exchange links with the studio and competition websites
I actually took a client to #1 for dance shoes and ballroom dance shoes, and #10 for shoes a few years ago, and they are still ranked well today.

I don't think you can do this online. You really need to get on the phone with some people to really start making this happen.