In order to know how to draw people (and animals and flowers and everything) and once you keep in mind the human body proportions you must simplify what you see in terms of geometrical patterns and convey the idea of the three dimension based on the most simple sketch you can make..
Some methods can be used with increasing difficulty.
Firstly we can use
simple lines and circles.
Draw the head (a circle). This will give you the dimensions already.
Here the exercise is to train the right proportions of the body, arms and legs and arms above all ( I tend to make the legs and arms shorter).
The pivot points can help us in locating the right position of upper arms and lowers arms, upper legs and lower legs.
We can use this picture to help us. I used a normal grid paper from a block-notes and started drawing looking at it.
HOW TO DRAW PEOPLE - METHOD 2
Then we cou use use boxes or I would say match-boxes to convey the frame where to "hang" the details further on.
You can see how "rusted" I am !
Here is much better site which explains it all!
HOW TO DRAW PEOPLE - METHOD 3
Then we could use spheres, the ellypses and cilinders in an increased degree of difficulty.
This is a very famous and capital chapter of the Bible which I like very much. it's immortal. Our heart hasn't changed in the end...
Ecclesiastes, Ch. 1, 1-18
1 The words of David's son, Qoheleth, king in Jerusalem:
2 Vanity of vanities, says Qoheleth, vanity of vanities! All things are vanity!
3 What profit has man from all the labor which he toils at under the sun?
4 One generation passes and another comes, but the world forever stays.
5 The sun rises and the sun goes down; then it presses on to the place where it rises.
6 Blowing now toward the south, then toward the north, the wind turns again and again, resuming its rounds.
7 All rivers go to the sea, yet never does the sea become full. To the place where they go, the rivers keep on going.
8 All speech is labored; there is nothing man can say. The eye is not satisfied with seeing nor is the ear filled with hearing.
9 What has been, that will be; what has been done, that will be done. Nothing is new under the sun.
10 Even the thing of which we say, "See, this is new!" has already existed in the ages that preceded us.
11 There is no remembrance of the men of old; nor of those to come will there be any remembrance among those who come after them.
12 I, Qoheleth, was king over Israel in Jerusalem,
13 and I applied my mind to search and investigate in wisdom all things that are done under the sun. A thankless task God has appointed for men to be busied about.
14 I have seen all things that are done under the sun, and behold, all is vanity and a chase after wind.
15 What is crooked cannot be made straight, and what is missing cannot be supplied.
16 Though I said to myself, "Behold, I have become great and stored up wisdom beyond all who were before me in Jerusalem, and my mind has broad experience of wisdom and knowledge";
17 yet when I applied my mind to know wisdom and knowledge, madness and folly, I learned that this also is a chase after wind.
18 For in much wisdom there is much sorrow, and he who stores up knowledge stores up grief.