Posing for a photo sometime it could boring, unless you are a professional fashion photographer than thats something different. A photo should tell a story and posing doesnt. So one of the tricks you can do is aim a camera to the person who you are intending to take a photo of, make sure he or she is not watching. Than once you have your settings done, shout at that person, if you know them call thier names, if you dont just do a strange shout. The idea is that person to get to see you, and at that moment snap a photo, you will be surprised of the out come. The above photo of my daughter is an example of that and as well the photo of my wife and son below.
PS/ Make sure you shutter is high enough to freeze the subject for this particular tip, otherwise you will end up a blurry photo.