Four Square Drill

Use alignment sticks at home (or tape on the floor), or tees at the course, to create a visual grid with the golf ball at the center of the intersection. This will help you be able to SEE the path of the club through impact. I like to number the boxes for easy communication with students. If you use the 1,2,3,4 designations that I outline in this video then understanding club path will be easy. Staying in the odd boxes will help you have an inside-out and shallow path, and staying in the even numbers will heal you have an outside-in and steep path. Use this drill to fine-tune your body's movements and how it affects your path. 

Your feels are lying to you

The ball flight never lies to you. Sometimes it is confusing, but it never lies to you. If you "feel" like you swing the club way to the right, but the golf ball starts straight and curves to the right (for a right-handed golfer) then you know that you swung the club from outside to in (even boxes). It doesn't matter what you think you did, what you did is what produced the ball flight. Once you have a solid understanding of reading the ball flight, then you have a good chance to be able to make changes that will make it fly the way that you want to.  Use this grid system on the range (or course by yourself) to help with your alignment, but more importantly to help give you a consistent path reference frame to speed up your learning.