To properly draw a character, there is an essential benchmark: proportions. Knowing the proportions allows us to control our drawing and to conserve the right templates when a character is reproduced many times such as in comics or animation.
The most common way of measuring one’s character is working "by head", this will serve as a key reference. There are several templates for drawing a realistic human being, you can use a system of 7 heads up to 9 heads, but for the example below I chose 8 heads because it can easily be subdivided.
You must use your own drawing as a reference, for example the hand is the same length as the distance between the chin and the top of the hair. We must learn to see all these references to help us check our proportions.
The member that is in motion on the same plan must conserve its proportions.
Of course, the system of 7, 8 or 9 heads is only valid for characters of "realistic" size. In the case of a "deformed" character, you must always measure by head, but readapt everything, like in this example of a character made with 2 and a half heads.
Above all, do not be a prisoner of proportional measures. A character moves, and inevitably an element that is closer gets bigger, and an element that is further gets smaller. We can see very well in this example how the hand has been enlarged proportionally to the head to show that it has moved forward.