Being a photographer who shoots people in some capacity requires the distinct ability to readily socialize with near-complete strangers and build engagement and trust in a relatively short timespan. For those who are introverted and/or socially anxious, that challenge is doubled. Here's how one successful photographer deals with that.
When I first started riding horses, I was put on a very feisty thoroughbred that was a bit beyond my ability to handle because he was the only horse in the barn big enough for my tall frame. For the first few months, every ride would eventually devolve into bucking and bolting, and it wasn't until I realized that I was the root of the problem that things got better. I was telegraphing my own anxiousness to the horse, and he was responding by assuming he had something to be worried about, which created the vicious circle that led to disaster each ride. When I learned to project a sense of calmness even if I was a ball of nerves, things instantly improved. It's not unlike that with a client; if you project condience and "take comfort in their discomfort," as Ortiz' wife puts it, it can be much easier to work. Check out the thoughtful video by Manny Ortiz above for more thoughts on the subject.