Visiting a Business Owner Unannounced?

Maybe a dumb question... but for those who’ve done unannounced drop-ins to introduce yourself to a specific business owner, what’s the right way to do it without causing a scene or coming across the wrong way? I’m thinking of situations where the owner is on-site, but employees and customers are around. How do you walk in respectfully, position yourself, and keep it low-key? What do you actually say, and what (if anything) do you leave behind? I’d love any tactical advice from people who’ve done this well (or learned what not to do)