When given a two-dimensional drawing of a character, a modeler must draw upon both anatomical knowledge and a sense of aesthetics to design the volume of the figure. Even when given both drawings and a three-dimensional maquette of a character, the modeler must still design a polygonal mesh that best translates the character into a computer model.
A model that has too many polygons will slow down both interactivity and render times. So, the modeler must keep efficiency in mind, using as few polygons as possible without sacrificing quality. However, in some instances using more polygons will speed up render times (e.g.: subdividing the floor of a furnished room) and interactivity (e.g.: Tripling a point-heavy "n-gon").
Modelers thus make a judgement call with every button pushed, with every point edited. With each button pushed, the modeler decides: "This gets me the results I want in the shortest amount of time." With each point edited, the modeler thinks: "This makes the model look better."
Experimentation teaches us how to use each tool in Modeler, but experience will teach us when to use each tool.
Note: In this tutorial, we will spend more time editing existing points and polygons than creating new ones. Learn how to select geometry quickly in Modeler, because most of the time you will want a tool to affect only part of the model, not all of it.The Display tab has great Selection tools. It also has Visibility tools devoted towards Hiding selected/unselected areas from your sight, so that you may have an uncluttered view of what you want to change.