Baby book. Monthly picture on one side, text on the other about the month. Take it a step further by taking their picture with the same thing every month so you can see how they've grown... @Leza Schoonover-Strayer
This. If you can't get them to sleep for your session, and they are too young to smile for you, this simple set up is the money shot. Place in front of a window with indirect light to add those sparkly catchlights. Winning.