Thanks for the advice, everyone! I have photographed family and friends before, but it's never been very successful because they're used to the "say cheese!" type of photograph where they think they have to ham it up for the camera even when I ask them to please don't. And, the expectations are different, as jnanian mentioned. So far, I've only managed two portraits of someone close to me that don't look stilted. Clearly, I have to keep practicing!