[bartozone]

Being completely honest about your intentions is the best approach. For instance, tell them you're working on a new product and you think it could be helpful to someone who owns a business similar to his/hers. Say you know they're busy (all SMBs are), and ask for a couple minutes of their time to just explain what you're hoping to build and if they would give you any feedback. If you have a BETA product, offer to give it to them for free with no commitment to buy. Just make it really easy for them to say yes and make it OK for them to say no, or not even respond.

Showing up at their work is likely not going to get you what you want because their day is probably already scheduled and it could be a pretty big inconvenience. Or likely a major waste of your time. Let them schedule through email. I'd be willing to bed if you get 10 - 20 email address or companies, you'd get a couple responses agreeing to a phone call or company.

Make your first interaction short (5 - 10 mins) and work to develop that relationship as they could maybe even become your first customer.