The ever present business card is often one of the ways our clients and our prospects remember who we are and what we should do. What do you differentiate from others? Is it an unusual color? Embossing? Different kinds of inks? A memorable image? A hole in the map? Decide things such as this should help show you through the design. If you've your company name and telephone number scribbled down on a torn little bit of paper, your customer will think your actual work or strategy is of similar quality.
The less risk that stores take in stocking your physically small, and expensive product, the more inclined you are being stocked.