When performing the Snatch, be conscious of sweeping the bar back towards you as you begin your first and going into the second pull.  The bar should literally brush the top of your hips at the top of the second pull.  See the picture above and notice the path of bar.  The lifter sweeps the bar back towards himself.  By doing this, you prevent yourself from being too far in front of the bar, consequently, jumping forward to catch the lift.