TEXT: This first step is important to understanding how the hand is constructed and were the pivot 
  points are. Once you are comfortable with the proportions of the hand it will be easier to draw 
  it in different positions. For now let's concentrate on the basic "Spread Fingered" hand. Follow 
  along and study your own hand as you go.
  Hands : Step 1- the oval
  Draw an oval. Much like the 
  one you see to the left.
  Designate a point on the lower 
  center line of the oval. This is 
  the anchor point we'll use for 
  our fingers.
  Hands : Step 2- radials
  Draw 5 lines radiating out 
  from the anchor point.
  The longest line will be the 
  middle finger...make it just 
  slightly shorter than 2 oval 
  lenghts.
  Hands : Knuckle placement
  The remaining finger lengths 
  fall on an arc from the height of 
  the middle finger. The knuckle 
  closest to the tip of the finger is 
  slightly less than 1/3 the way 
  down from the finger tip. The 
  next knuckle splits the 
  
  difference between the 
  remaining length to the top of 
  the palm oval.
  The thumb has 3 knuckles as 
  well but the anchoring is hidden 
  inside the palm.
  Hands : Fleshing in
  Flesh in the fingers as shown 
  here. The fingers start narrow 
  at the base..widen at the first 
  knuckle then taper down again 
  toward the tip. Believability is 
  added by drawing creases in 
  the places the hand bends the 
  most...at the knuckles and 
  along the palms. Look at your 
  own hand for reference. 
  Everybody's hand is slightly 
  different. This hand is 
  definately mine. 
  (Notice I am Right handed and 
  that's why my hand model is a 
  Left hand)
  Hands : The opposable 
  Thumb
  The thumb kinda has it's own 
  thing going on. It rotates 
  around on its own axis. The 
  thumb swings inward on its 
  Anchor Knuckle and bends 
  down at its second knuckle to 
  point at the base of the Ring 
  finger. The thumbs arc peaks at 
  the middle knuckle of the index 
  finger.
  
  Hands : Finger lengths
  The Index finger and the Ring 
  finger are nearly the same 
  height..about the halfway point 
  of the middle finger "tip". The 
  Ring finger is just slightly 
  longer.
  The Pinky finger comes up to 
  the last knuckle line of the Ring 
  finger.
  Notice how the hand is not 
  Square but Wedge shaped.
  Hands are a nightmare for most artist...myself included. It's hard to contruct it in basic shapes 
  so I don't really try. Instead I break it up into major forms and really pay attention to where it 
  folds and bends. MAKE SURE YOU HAVE READ THE FIRST HAND TUTORIAL! This one 
  doesn't deal with proportions like the other did. This is more the form of the hand.
  The hand is kinda like a 
  shovel...that's what we use it 
  for somtimes. You're palm 
  gives you the lines you need to 
  see were it bends. Above the 
  top blue line is the first row of 
  knuckles.
  Don't make the hand a flat 
  wedge. It curves and follows 
  the contours of the lines on the 
  palm. Notice how the thumb 
  side of the palm pivots from the 
  center.
  even when drawing the hand 
  from the back..pay attention to 
  the fold lines in the palm. It will 
  help you draw more natural 
  positions for the thumb and 
  fingers.
  Below is a series of hand studies I drew based on the above diagrams. I kept some of my 
  stucture lines in tact so you could see what I was thinking when I drew them
  
  The Foot: Know your basic forms!
  Like everything else you draw, the foor also consist of basic forms. 
  I break it down into 3 parts. 
  1) a cylinder for the shin
  2) a half a peanut for the front 
  3) A roundish shape for the heel
  Side view
  Here you can kinda see those basic shapes beneath the foot.
  The shin comes into the ankejoint which then branches back for 
  the heel and forward to the toes. Notice the foot does not sit FLAT 
  on the ground plane..there's an arch between the toe pads and the 
  heel pad.
  If the shoe fits...
  A shoe is basically just a wrap for the basic foot shapes. Looking 
  at pictures of shoes will give you ideas for styles. Here I chose a 
  modified US Army Jungleboot. Make sure you make the Sole of 
  the shoe go below where the bottom of the foot would be. There's 
  about a 1/4 of an inch to 4" of rubber between the bottom of the 
  foot and the bottom of the sole.
  If your stuck...
  Draw the foot first. That will give you a better idea on how to wrap 
  the shoe around the foot form.
  
  the Wedge 
  Notice how the foot is shaped like a rounded wedge the bend IN 
  towards the body's center. The toes are also arced like the fingers 
  of the hand...the middle toe is usually the longest.
   
  The Instep 
  Okay, this foots a bit wide but you see the important structures. 
  Everyone's seen foorptints in the sand. The heel and Ball of the 
  foot are linked by the outside edge of the foot. The arch of the foot 
  doesn't come into contact with the ground. 
   
  Mastering forms in perspective
  Once you understand how a foot is put together you can start 
  getting creative with action poses. Take a good look at those basic 
  shapes I drew in step one and see if you can find them in this 
  drawing to the left.
  Practice Practice Practice!
  
SOURCE: textdata/thevault/Crafts/Design/Cartoons  Comics  Fantasy/How to Draw Manga/How to Draw Manga - Hands and Feet.pdf