The hand and feet, is not to hard if you know the structure and anatomy. My tip is for you study the structure and anatomy, if you know that, you can represent as you want! It's very important to know the bones, muscles and action of them.
I'm not taking into consideration the fundamentals of drawing, this is like an alphabet when you started writing your life.
Perspective 1, 2, 3 point.
Shape: (cube, sphere, cone, cilynders etc.)
Plans: (square, ellipses, triangle etc ...). And proportion of head and body, simple muscle groups, light and shadow as well.
I recommend you searching for Drawabox on youtube. ^^