I really try and take a relaxed approach to family pictures. I get the group and posed shots out of the way first because kids tend to lose interest fast. Then, I just let the kids do whatever they would like and I take pictures as they have fun. I will direct them a bit but really what I want to capture is them being happy. Even my kids look strange when I ask them to smile for the camera. Parents will often try and be helpful by telling the kids to smile while standing behind me, although I appreciate the help, in this case it's best to let me do all the asking as kids will often get confused on where to look as well as feel pressured to take pictures and that usually ends up with them wanting nothing to do with the camera. Just relax, some of my favorite shots are those with no requested smiles.