There are so many times growing up that I blew it with girls because I figured that they were just being nice to me. I would tell myself to assume that the positive interest that came my way was exactly what I thought/hoped it was, if only just to go for it. Starting with that time when I was 9 and that girl asked me to go to the beach with her alone, but then I got a nervous stomach ache, put down the receiver and asked my dad what I should do (he made fun of me).

I would also tell my kid self that math doesn't suck and to ask my parents to get me a math tutor who could show me how I could actually use the stuff.

I guess I would tell my kid self to continue playing sax and not to give up guitar. And also to learn properly how to draw, as well as to continue with the pottery.

Finally, I would tell my kid self that going to prep school is a good idea and that when the opportunity arises when we are 14, that we should take it.

That is a really cool idea for a documentary. I should watch this.

Edit: ah, 7 year old self. I guess I would tell him to do all that stuff above, but tell him that it's future stuff.