I stumbled upon this great article from the Biz Box Blog that has excellent information for crafters wanting to break into the retail market with their handmade goods and are not sure where to begin. Great advice, terriffic blog.
I have always thought the biggest obstacle is yourself when trying to penetrate the retail market. Being afraid of getting turned down and not having enough confidence in your product or yourself seem to be the greatest hurdles when I talk to other artists/craftspeople about selling retail or wholesale. What I did was make sure that I had a flawless product, took a deep breath and pretend that I've done it a hundred times before. It seemed to work :-)
Also here is another well-written article from a Posie Gets Cozy . Excellent advice and how-to!