All children have different personalities, so it really is difficult to predict how each one is going to react to going to the first day of kindergarten. Some children will walk off without so much as a backward glance at their parents. In this situation, it's usually much harder on the parent than it is on the actual kindergartener. However, sometimes the child has a more difficult time letting go, and the parents may need some advice on how to best prepare them for their first day of school.
Most importantly, begin talking about the fact that your child will be going to school far in advance, to get him used to the idea. Bring it up in casual conversation without making a big deal out of it. Try to speak matter of factly about it, as if it is simply a natural progression, and the next step in your child's life. Sometimes, you may want to mention some of the fun things that your child will get to do in kindergarten, but some children will see through this tactic and may feel that you are trying to trick them. For those children, it is best to stick with the matter of fact approach.
In the months leading up to the first day of school, make sure that your child has opportunities to be apart from you on a regular basis. Play dates with other children, visits to family members with other children to play with, neighborhood play, or even staying with a babysitter from time to time, will all help your child become more comfortable with the idea that he will survive without you.
As the first day approaches, ask your child if he would like to take something from home with him to the first day of school. Something like a small token or stuffed animal can be easily tucked into a backpack, and may give your child that added comfort that he or she is looking for.
If your child is visibly stressed, don't embarrass or punish them. Don't try to force them to relax or to not be anxious. These tactics will only make the anxiety worse. Instead, tell your child that what they are feeling is normal, and it is OK to have those feelings. Assure them that you will help them deal with their feelings so that they can learn how to become calmer about going to school. Speak with their teacher privately so that the teacher knows your concerns. Usually, if you can get your child into the classroom, and the teacher can engage him or her in an activity, you can say goodbye and they will adjust comfortably.