Personal selling, for products or services, is often ignored in favour of volume, but you can often score plenty of quality leads and repeat business from showing a friendly face in initial interactions. Treat every enquiry or browser as a potential customer. They may not buy right then, but if you treat them courteously, they are likely to remember good service and return in the future.
Be personable but not too familiar; being too familiar might lead customers to think that you assume you know what they want. Being personable is largely about being open to hearing about their needs and helpful when it comes to suggesting a suitable product or service.