Inspired by a cute children's book called The Kissing Hand I gave her 2 little kisses on each hand. I told her these were my kisses that she could take to school with her. Then I took a purple Sharpie marker and drew a little heart where I had kissed. Then if she was feeling sad at school she could put her hand up to her cheek and have a little kiss from me.
She then wanted me to have a kiss from her. So she kissed my hand and had me draw a heart too.
This least gets her in the door, and then she usually has fun. None of my children are very clingy. But if any of them got close, it's Baby Girl. She's my one child that did not like nursery at church for 6 months. So this kissing hand thing was my last source of hope.
And so far this is working . . . at least for now.
I would appreciate any other ideas you have about clingy children or saying those daily goodbyes.