You're doing it correctly. 8-sided cylinders are perfect for modelling humans, and doing each limb as a seperate cylinder is a perfectly fine way to go about it, especially because using the cylinder method, there is actually a really good merge point for the arms to the torso that you can get, keeping all edge loops in-tact.
The edge loops could be a little smoother on the side, but they're decent. You seem to be getting the "superhero" torso problem however; where the torso tapers upwards too much. Im pretty sure its because of where you stopped on the arms. I usually tend to model the arms past the arm-pit, and merge them with the torso there, whereas you modelled them right to the armpit, and made the torso conform to fit. You can fix it by adding some loops to the armpit area.
Overall though you've got the idea down, it just needs some practice. Your reference images are a great choice. As you see more mesh's of other human models, and pictures of the human anatomy, you'll get used to the proper mesh flow over time.
