Here is a test. Hit your 7-iron, then hit your 5-iron. If they go about the same distance, with the same low, weak flight, I already know your problem. You are swinging with your arms.
Most golfers are all arms. The body barely turns, the arms do all the work, and every club produces roughly the same shot. No rotation means no speed, and no speed means no distance. You cannot out-swing it with effort. More arm effort just makes it worse.
Real power comes from rotation. Full rotation means your eyes, shoulders, hips, and knees all face the target at the finish. When your arms stay tucked, biceps lightly against your sides, the body does the work and the club releases naturally instead of flipping. You get speed you did not have to manufacture.
Here is your checkpoint, and it is dead simple. At the finish, the sole of your trail shoe should be pointing up at the sky. Weight on your lead foot, trail heel high, laces to the sky. If you can see the bottom of that shoe, you rotated. If your trail foot is still flat on the ground, you did not.
Drill it like this. Make a few arm-only swings first, no body turn at all, so you feel how weak that is. Then make full swings where everything rotates to the target. Biceps stay lightly against your sides. Finish tall with the sole of the trail shoe showing. Hit 8 to 10 balls thinking about nothing but that finish position. The distance will surprise you.
The mistake: sliding instead of rotating. Golfers hear "turn" and sway six inches off the ball, then wonder why contact got worse. Rotation happens around a stable base. Your weight moves to the lead side, but your head stays relatively steady and your hips turn, not slide. Turn, do not sway.
Arms alone will never give you real distance. Rotate everything and show that sole.
The video version is in the Pro Vault along with 220 more drills, a dollar a month at coachellapro.com. Or book a lesson and let us build your rotation together.