Represent all ethnicities in your classroom materials, especially pictures and posters, that toddlers see on a daily basis. If the toddlers are not exposed to people of a different ethnicity on a regular basis, it is doubly important to include other races in classroom materials. You don't need to talk about it; simply having them in the classroom helps toddlers begin to see diversity.
Sing songs, watch videos and look at books that represent different cultures and different lifestyle choices, as well as different types of family life. Exposing toddlers to these activities creates an environment that is diverse for them.
Structure your classroom time around many different activities, such as reading, playing, singing, quiet time, and outdoor time. Doing many activities will help create an atmosphere that allows toddlers to experience the classroom with all of their senses.
Set up rules and guidelines for your toddlers in all classroom activities. Although diversity within the activities is encouraged, it is important that young children have limits so that they can feel comfortable exploring.