Hold an open house for parents. Let them see their child's preschool classroom, and show them work that students recently completed. Take the opportunity to ensure all parents have your contact information and that they understand what is expected of them.
Talk briefly to parents before or after class. Encourage them communicate with you if their child is sick, didn't sleep well overnight or did not eat breakfast. After class, advise parents of any concerns you have about their child, including physical and behavioral issues.
Produce a newsletter or website that you update frequently. In these updates, mention concepts or skills you are currently teaching, future field trips and suggested activities for parents to do with children at home. You may wish to include a thank-you section in the communication, where you can recognize parents' and students' contributions to the classroom.
Encourage parents to volunteer in the classroom. Parents can help by tutoring or reading to students, chaperoning field trips, helping with preschool events or bringing in needed supplies.
Organize parent-teacher conferences, and gather information beforehand on each student to discuss with parents. For example, if you are concerned about one child's social skills, bring a well-kept log tracking different instances in which the preschooler showed a lack of these skills.