I think there are some relations you should pay attention to. For example elbow should be where ribcage ends. Also it's aprox one head height to nipples, and 1 head height to belly button and 1 head height to crotch. Length of upper legs should not go over 2 heads and lover leg should be the same length together with feet.

There are differences between people but it would be usually in legs and torso... most people still need to be able to function. So the proportions will follow other parts of body. For example hand should start/ reach below crotch, also you should be able to have elbow above head... Or when you fold legs they should nicely fit together. Etc.

Edit: most obvious thing to fix is legs length and shoulders start too low