A lot of the neighborhood kids come over to my shop after school and want to help me or build their own projects. I will not let them use power tools so I bought a cheap 20" stanley combo hand saw for them to use. I've successfully taught half a dozen halflings to saw a decent line, but the oldest (11 years) can't saw straight to save his life. He is smart enough that I told him we could build a bedside table when he can saw a straight line. For some reason he just can't do it even though his 6 yr old neighbor can do it.
I don't really know the "right" way myself, here is how I've taught it. I draw a line for a crosscut for a 1x6 of pine (for a birdhouse). I clamp the board and then clamp a piece of scrap adjacent to the line for a fence to help keep the saw aligned. I have them keep the saw, their elbow and shoulder all in the same plane. The smallest ones are so weak I let them do whatever comes naturally and they seem to pick it up very quickly.
Any tips? I'm not a very good teacher and I just can't seem to figure out his problem. I hate to see him get so frustrated, he has problems making/keeping friends and I don't want this to become another problem.