Kids and clothes can be washed. (Discovered that one is hereditary.) (And it came back to bite me when my grandson quoted it to me as I commented on his shirt!)
Little girls are worth way more than butter dishes. (Still consider this one of the best things I ever said – it was my grandmother’s butter dish and she would have agreed.)

It’s the opinion of the person in the mirror that counts. (If you’ve lost your self-respect you’ve pretty much lost everything. Do what you know is right for you.)
Out-nice the meanies and the bullies and you will be proud of yourself. Nothing disconcerts the bullies as much as not being able to get to you. (Hard one, especially when you are small. Kids can be so mean.) 
Do your best.
“Success lies not in being the best, but in doing your best.”
On the fridge for decades.
Keep your head up and backcheck. (This is a whole other post; stay tuned)
I may not like what you do and you may be able to make me stop liking you for a while but you can’t make me stop loving you. Don’t even try.
Call anytime. I will come and get you, no questions asked. (Still applies, calls would be for different reasons now.) This one takes patience when they call as teens and you are already asleep. Worth it though.
Did you do it on purpose? No? Then quit worrying and get on with it. (The way I grew up made me reject shame and guilt. People are the most important.)
This above all: to thine ownself be true. (Stolen from Shakespeare. When the incoming head of school quoted that at my daughter’s grad everyone probably wondered why she laughed.)
Don’t sweat the small things. I learned this from the Head of our school. Don’t argue about hair and earrings and makeup. Save it for the important things like values and behaviour.
Carpe Diem
I reserve the right to add to this.