The human body can be split into 8 sections to help accurately measure the proportions of the human body.
Proportion can be extremely difficult to master. Drawing out these lines (with consistent spaces between each), and practising the positioning of each part of the anatomy can help to cement correct composition into your mind to be drawn from in future drawings.
These lines and new found knowledge can be applied to bodies in other poses in short (without having to sketch out guidelines).
Lesson 1. The Human Form
The initial figure can be constructed using base shapes to build the pose. The body can be simplified into quick easy to draw 'building blocks', which can help to work out an accurate pose.
They can be drawn by lightly sketching with your pencil, so they can be easily erased. You can then apply final lines over top and hopefully the initial sketching lines will then, not be visible.
Once you are happy with the composition of the pose, you can then begin to define the final shape by erasing the initial lines (shapes), and adding the final detail lines. You can then begin to add details such as fingers, toes, muscle lines, and wrinkles to complete the image.