I almost every year have kids going to jk. The preparation is done way before, a lot reading and talk and visit to the schools meet the teachers etc.

When the time comes we do something special go somewhere especial or bake something especial. I always tell my future jk s to give us a visit and tell us about school. (And they do, whenever they feel they mis daycare, at the end of their day they come for a visit, it is part of their transition) eventually they come to realize I'm also there to support them emotionally.

And yes a gift is a good idea. Something that they use at the school, I got stainless steel water bottles and the daycare group placed stickers, also books etc.