Enjoy them as much as you can, because believe me at some point you are going to miss them a lot.
I understand :)
Dont worry most people cry, the staff know what they are doing :) if you have to leave your kid crying hide out of site for about 10 mins you will see as soon as your out of site you are forgotten about and they enjoy their day. Pack extra clothes and even shoes there is wet play and messy play and kids get stuck into both! Just remember to enjoy your peace and quite for as long as it lasts when they come home the first few times they will be very tired and grumpy expect this and you can avoid tantrums that are not needed :)
Beeee sure to tell'em not to bite the other kids!
talk it up like it is an adventure (to sidestep abandonment issues)
ask a lot of questions when they get home (so interest)
praise all they create (foster self-esteem)
i never been in a preschool, you worry too much
im not a dad so i got no idea what to do.