What I learned (when my child was) in Kindergarten

1) If they're supposed to eat breakfast at school, tell them so -- every day. Because if you don't, they won't, and they'll say "Well, you didn't tell me to!"

2) Even if you buy a special fancy hairbrush and keep it in their backpack, they won't brush their hair at school, no matter how stringy or ratty it gets.

3) Don't buy them markers that smell like food - the temptation is too great, and they will taste them. And they will coax the other kids into tasting them too. And the other kids will then have to taste their own markers, even if they don't smell like food.