You could always try to get them interested and talking about their ideas before you even show them the portfolio. It may help to make them feel like you're getting to know them a little better before you do the work for them and the fact that they feel they are dealing with you on a personal level, may help them to be more interested in hiring you.

This is probably a terrible analogy, but I feel a lot better when I talk to a live person on the phone, then a machine that's just monitoring the buttons you press on the phone, because it feels more like a personal experience, not just a customer with a number kind of experience.