Every artist that ever lived has had trouble with hands.  You can try workarounds like placing your subject's hands behind his back, or hiding them in pockets, or drawing "mittens" instead of individual fingers, but you're not fooling anyone.  Someone looking at your picture is going to think, "Aha – there's an artist who can't draw hands."  

So bite the bullet, and let's get started.  Examine your own hands as you follow along.  
 

Here is a simple tracing of a hand for illustration purposes.  Hands are a collection of many small bones connected with cartilage and muscle.  They are flexible and strong and have many small moving parts.  They also have very distinct proportions.  Why couldn't we have tentacles instead, eh?  In order to draw them, you have to break them down into managable bits and know what is important to get in your drawing.  

This is a hand, knuckle side up.  The first feature you should identify is also the largest – the back of the hand.  It forms a squarish shape, wider where the knuckles are and narrower at the wrist.  This is the foundation for the hand.  Secondly, note the placement of the joints of the fingers (marked with circles).  Joints are useful because 1) they mark where the fingers bend and 2) they are a distinct thickening in the shape of the finger.  Fingers are more slender before and after the first joint, particularly in women.  Fingers do have three joints including the knuckle – there is another present between the first joint and the tip of the finger not indicated in this illustration, because it plays a minimal role in most hand gestures and you can safely ignore it most of the time, unless the hand is grasping something.  We will concentrate on the knuckle and first joint for now.  Thirdly, note the largish oval that indicates the muscle pad at the base of the thumb.  This muscle pad helps build up the shape of the hand, particularly the thumb, so don't neglect it.  The thumb has two joints.  One is located at the pointed end of the oval, and the second is indicated by a small circle.  

This is a hand, palm side up.  The palm side has the muscles and flesh of the hand, while the back side is bony.  The most prominent muscle/flesh areas to remember are: the largish oval at the base of the thumb, the ridge of muscle that runs along the side of the hand, and the strip of callouse or thickened flesh that pads the palm side of the knuckle joints.  Also, each finger is tipped with a pad of thickened skin.  These thicker, muscular areas play an important part in making your hands seem more lifelike and solid.