I found on the internet a "recipe" for measuring the body in relation to the head. Things like accross the shoulders is two heads, the lower leg in two heads and so on. This of course does not take into account foreshortening. I tried to correct the drawings, but it did not work out. I am keeping the recipe for future reference though.
I want to go regularly to life drawing sessions, but I will need some kind of plan to approach drawing the figure. The road ahead is long ... but fun.