Before we begin, we should note an important feature for this project and all other modeling projects involving poly modeling: the face normals. Every face we create has something called normals pointing in a perpendicular direction from the face. The face normals set the visible side of the faces and can be decisive to export the model later to external renderers like YafaRay. Even if this is not a primary concern now, the normals of an object can always be verified with a simple button available in the editing panel of Blender. The following screenshot shows the location of the button:
Press the Draw Normals button and the normals will appear as small lines pointing out from the center of the faces in the 3D view of Blender.
If a model turns out to have the normals pointing toward the wrong direction, we can always change the normals with an option available in the specials menu. In edit mode, press the W key and the specials menu will appear. There we will find an option...