In our vast combined experience integrating children into the preschool environment, we have found that children separate best by: first, having visited the school a couple of times, playing on the playground, etc. and familiarizing themselves with the building; and second, during the first few days of school, parents should give a quick kiss so-long, reassure the child they will be back and let the teachers take over comforting the child. It is our belief that children need to learn from the very beginning to trust the adults in the classroom and learn to feel safe and secure in their care. Our school does have extra staff on hand and some of the classes of younger children have an abbreviated schedule during these first weeks; however, it is our goal to make each child feel welcome and safe as quickly as possible. One of the primary goals of our school is to help children learn to trust other adults in their world, and we begin this process on the first day of school.
Yes, sometimes children are upset as their parents are leaving. Yes, some children do not initally want the teachers to pick them up and comfort them; in these situations, the teacher stays close by and talks to the child, reassuring him/her that he/she is safe and that "mommy or daddy will be back soon". The teacher will then attempt to engage the child in play and interacting with the other children until he feels better.
We have experienced great success with these methods and most of our children acclimate within a day or so. In rare cases, in conjuction with parents, it is determined that the child is simply not ready for school yet and should wait a little while. We strive to make each child's preschool experience a positive one and never want a child to associate negative feelings for school.