Well today was the first lesson, and I got to know the kid's basic skill level. Also, it turns out the child is six.
I think he definitely has potential, but he still has a lot of consistency issues. The main thing I taught him today were grips (forehand and two handed backhand), proper takeback (early preparation), and follow through over the shoulder. I also told him to constantly watch the ball and make sure he knows where it is.
He seems to be progressing well, but sometimes it seems like he's just waving the racket in the direction of the ball and completely missing it because the head goes into a horizontal position. Any tips on how to make sure he impacts the ball properly (and also in front of his body)? Maybe this means that the racket is too heavy/big for him?
Once we're at the point that he can hit pretty consistently, I'm going to play a few games with him, to make it more interesting.
Thanks again for everyone's help!