IMPORTANT TIP "It can be helpful to gather a little information about [the children] before you begin the session. In my pre-session consultations I ask the mom about her toddler’s favorite songs, TV characters, etc. This way I can more quickly enter into their world once I meet them."
Lighting 101 from The Stobist. This video is pretty much the best thing ever. It's the basics of lighting, what stuff means, and what equipment to use. I'm not ready for this level of photography yet, but it definitely helps me to think about composition a little more.