People have mixed feelings about being photographed. The people who hire photographers for an even have mixed feeling about being photographed. Photographers themselves have mixed feeling about being photographed. Partly this is because we have seen unflattering photos of ourselves; partly this is a mystery held back by some vanity issue. Either way, there are some ways to deal with it in other people.
HAVE PEOPLE SIT DOWN: For some reason many people are less self-conscious this way. It’s worth carrying a portable chair to events for the sake of getting a few good shots of a few individuals.
DO SOMETHING WITH PEOPLE’S HANDS: Again, less self-conscious. This even works with some children.
DISTRACTIONS: when people deliberately try to pose they usually look unnatural. Professional models work hard to get past this issue. Children can be inspired to give a natural looking response from a toy or other novelty. Occasionally a child will respond well simply with the knowledge that they are the centre of attention. Adults require something more, but a person responding to something out of shot is a promising opportunity for an image.
SPONTANEOUS: There are staged shots and there are moments that are captured on film. If you are unobtrusive and follow the subject for long enough you will find a few great moments. Always go for a potential great moment of spontaneity.
An art that is acquired rather than learn is dealing with people. For the staged shots just the ability to look professional and make others enthusiastic can make for far superior images. If people want to work with you the results will show it.