“Compressing” the ball on iron swings is one of the best feelings you can have. A lot goes into it, but the main thing is delivering the club to the ball on the appropriate angle. Most rec players reach impact on too steep or too shallow a plane. Either error will produce a thud and not that happy click you get when you catch one pure.
Without getting boringly deep into mechanics, you can groove the correct delivery angle with the help of one of your alignment sticks.
Set one in the ground on the far side of the ball as shown below, positioning the stick at roughly a 30-degree angle. As you hit practice balls, use the stick as a visual aid to guide you on the ideal delivery plane, no steeper than the angle of the stick nor too far under it. In a few attempts you’ll get your swing where it needs to be as if by magic.
Bonus: Set the stick in the same manner on the other side of impact, with the rod rising from the ground up and toward your target. This is helpful if you tend to get too steep on your downswing.
Jim Murphy teaches at Sugar Creek GC in Sugar Land, Texas.