The key to drawing good and realistic looking feet is in studying the foot itself. Being that this IS a tickling site you shouldn't have a problem finding a picture of a foot.
Angles, proportions and foreshortening are all important in carrying across depth and tone to the viewer and gaining that appeal. The feet, in their own way, are just as important as the faces and hands of the characters you're drawing and just as expressive.
Even if someone gave you a tutorial to follow thats only their way of doing it and isn't necessarily the best way. Also consider that its their style, and you don't want to end up just copying it. You want your own. The only sure way you'll ever get the hang of drawing them is to study the feet in different positions and the toes in different positions as well.
Is there anything inparticular that you need help with?
