Of the 3 Olympic movements (Snatch, Clean, Jerk) the snatch is easily the most complex and most technical.  Why?  The bar has to travel the great amount of distance, its has the longest sustained bar speed, and uses the most amount of body movement at one time.
There are a number of reasons why we mess up the snatch and a number of recommended fixes for those technical failures.  If you have any knowledge of the Olympic lifts at all most of them are easy to spot.  However, fixing them are another problem altogether.
Bob Takano of Takano Athletics recent published an article honing in on one specific lifter’s problems and draws out not only the technical faults very well but also the recommended fixes.
Check that article out here.
Remember, every coach has a little different philosophy on how the lifts should take place and how best to correct faults.  I love the traditional perspective that Takano holds here but there are 100 ways to skin a cat.