Really good photos are achieved in one of two ways:
1. Take the photo when your subject is busy or doesn't pay attention. This way you can capture them in their natural authentic state. It works especially well with kids: the best photos of kids are when they're playing or busy doing something.
2. Go to the extreme. If you want to plan your photos or direct your subject add something crazy or funny. This will make the photo unique and interesting and will capture the essence of a person. Look at what my kids decided to take a picture of....me with a plastic bag on my head...I think it's one of my best photos, funny and unconventional..
So next time if you want to take a photo of your family don't have them stand in the room and smile, have them do something like a funny face, maybe jump or even stand back to back if you are more Conservative or feed them and take the photo while they're eating....
Have fun Creating!