@Rottbott: Think of the "bone" that the joint moves. For example, a hip joint would control the vertices to the femur/thigh. So you would assign the Verts of the thigh (from hip to knee) to the hip joint. Likewise, the knee joint would control from the knee, all the way down the shin, to the ankle. Some of the tricky parts are around the areas of secondary movement (the butt cheeks, and around the upper shoulders) when you don't have weighted vertices to affect them.