I don't know if this site was mentioned before, but figured go ahead throw it out here. http://hpc.artofuldis.com/
One obvious way is to use it to draw a blueprint. Looks like a great tool, especially for those of us who are just starting out and who struggle with keeping everything in proportion.
I use a different system, where I divide the total body height by 11.5 and get the 5-eye-length distance (width of the skull). And use the 5-eye-length line to get some bony feature landmarks. The advantage of this is that it is independent of head-height. There's another system, the proportional system, where you basically treat the head-to-pubic-bone distance and the thigh-joint-to-feet distance separately (overlapped at the hip), useful for when you want to draw longer-torso or longer-legged figures, for example if you need to differentiate men and women bodies. Found an example! That link illustrates 8-heads vs the 11.5 divisions. The 11.5 divisions is just a special case of the proportional system, where the top and bottom sections are equally tall.