What makes the best 100 mile support team?

I'm going to be on a support team for a 100 mile runner and I would love it if you could give me tips for the best way to help the runner. Thanks.

What did you discover?

This was a 3 mile loop course, so I saw the runner alot. Helping her through transitions to make them quicker: helping with shoes and socks, having ready what she needed, running errands. I brought homemade turkey and chicken broth that I heated by the cupful on a small backpacking stove. She loved this! Someone else had store-bought broth that she tried and hated. The salty drink was a welcome change from all the typically sweet drinks.