1) How old is that child?
Children's body proportion and faces are crucial to tell an age. As they grow, a big head gets smaller, a face is changing and they get taller. "Pratice makes perfect" is the best way to learn it. Just draw it for tens of millions times.
2) Find a drama and seize the moment.
Get a child's mood. Choose an interesting movement. A dramatic moment attracts viewers and very eye pleasant. I love sketch them!
3) Set an angle carefully
I'm very fussy about an aspect to capture a moving child. Very much like a hunter, I'm waiting for the favorite moment in a child's movement, while holding a graphite.
Daily observation allows us to capture the best moment on spot. In other words, if we do not try children everyday, we cannot either find children or seize them in drawing.
Just keep drawing.
Finally, I'd add, "Sketching childfren also gives busy you smile and fun!" Sure, kids will come to you and ask you, "Can I draw (with you)?"
Now, I'm preparing for the jammed schedule. I organise time and list up necessary things and what-to-do in order. Being well planned is crucially important to achieve a goal. Not easy, but I'll do my best. Thank you for warm and strong encouragements!!
You, too, Friends, Happy Painting and Drawing!