Many players have too much movement in their lower body in an effort to generate more power.
To improve the consistency of solid shots you need a solid base. Try making some practice swings without lifting any part of your foot, including your heel, off the ground. The complete practice swing is flat-footed. This will keep you “swinging within yourself”, with decreased lower body movement. This will lead to more stability and better balance.
Once you have made a number of flat-footed practice swings, try to duplicate that quieter lower body into your regular full swing. You will find better contact as a result of a quieter lower body.