What? You're NOT a business person? You're a stay-at-home mom? A blogger? A nurse? Maybe a student or a volunteer?
You're still selling something. We ALL have something to sell.
If you're a Christian, your very life should be a big ole advertisement for the life of a Christian. It should be the lit-up billboard by the side of a dark road that says, "Here's what you've been looking for." It should be the Super Bowl ad that people talk about for weeks afterwards. Your life as a Christian should be selling the Christian life.
Does it? Are you like-able? Do you genuinely care for those around you? Do you serve with compassion and honesty? (And yes, that means your family too - even when they leave their dirty socks and snack wrappers on the living room floor.) Do you treat everyone you come in contact with well? What happens when you get treated badly? How do you react? How do you smooth over problems, complications and disagreements?
I suppose, if you are a pessimist or a non-believer, you might say this is just an act. "Hey, you're just 'selling' a product and your product happens to be some guy named Jesus. You're all a bunch of phonies." I would say that if you're NOT being likeable, then you're a phony Christian. Our faith is supposed to give us joy, radiate love to others and be genuinely concerned for everyone we meet - not just the ones we like.
Are you the sort of person a non-Christian would want to "do business with", learn from, come back for more? If a non-Christian met you, would they buy what you're selling?