I know most people have been told to keep their head down (I cringe every time I hear this statement) but I want you to try and let your head move and begin to look at the target sooner. By keeping your head down this will cause you to limit your upper body rotation as it goes through the hitting area along with not allowing your weight to shift properly in your swing. Also, by keeping your head down you will not allow your arms full extension at impact.
Next time you practice, I want you to set up with your spine straight and your head up but you should still have your eyes on the ball. As you swing through the ball at impact don’t force your head to stay down but allow your head to look up at your target. This movement will create better body rotation, better arm extension and better weight shift which will lead to solid impact and further distance.