I've probably seen about every degree of nervousness when it comes to shooting portraits of people. There are those that come in having done it a million times that will move and interact and love the camera and eat the whole experience up. There are some that are terrified that try and hide and close themselves off and look away. And there are those that are neither... that with a little instruction can produce images just as good as the others.
That's right...even super nervous subjects can end up with amazing portraits. All it takes is a photographer that can bring them into a comfort zone... and subsequently break them out of it!
Today I shot for a girl (14) who had never done anything like a portrait session before. A friend asked me to do it as a favor and warned me she would be nervous. Since it wasn't my first rodeo I was able to put her at ease. One of the easiest ways for me to do this is to show them that I'm just a person... just like they are... and that I'm a bit silly.
Silliness always puts people at ease :D