Set up a playdate. New kids need friends, or at least someone with whom they can walk into the class with, so have the child over to play with your child and be sure to find out if the child has any food allergies to ensure their comfort.
Be a resource for the family. Suggest dentists, dry cleaners, grocers and what have you to help them settle in. Connecting with the parents enables the child to feel more settled as they see their family being embraced by the community.
Introduce the parents at drop off and pick up time. Many times, it helps to introduce new parents to parents who have children at the school. This makes the new child feel welcomed, too, so make certain you introduce anyone you know to the new parents during the busy drop off and pick up times at school.
Take a moment when you're working in the classroom with the child. If you're helping out, be sure to single the child out say hello and ask how they are. Don't ask how they like the class or the material as the response can be awkward, but be sure to greet the child and have a brief conversation.
Have the family over. If you find your child bonding with the new kid, invite the family over to get to know them better. Who knows? They may become a new best friend.