Hi there, I am a nursery teacher, and bracing myself for the inevitable tears and tantrums which face me tomorrow, after 6 glorious weeks holiday! (Not just my tears...)
I agree with the other posters, some very sensible advice, and can confirm, we would always ring a parent if the child did not stop crying.
Some other pieces of advice: agree a routine with your child before you leave home, and DO NOT negotiate once you are at the nursery, eg, We'll do one puzzle together and then I'll go to work...
Your child will settle better if he knows when the separation will occur. Resist the urge to stay if he says, just 5 more minutes.... those extra 5 minutes will not help him, and he will be controlling you. If he's going to cry, he will cry after 5 or 15 minutes regardless.
Don't stand chatting to other parents in the setting, not only will your child get increasingly anxious, not knowing when the separation will occur, he will also find it harder to get involved with other children/ activities.
Get down on his level and show an interest in the acivities on offer, if you don't seem enthusiastic, neither will he be! The staff usually have a learning goal in mind, so it doesn't help him if you DO the activity for him, yes he has a beautiful end product, but it is the process that counts.
Don't worry if he doesn't seem to be socialising while you are there, MOST children act completely different while their parents are there!! Also, we are paid to carefully monitor and support the children. Even if he wasn't socialising much, at this stage it wouldn't be considered abnormal, the staff would just focus on providing opportunites for him to share his interests with his peers.
Good luck, he will be great!!