To control trajectory with irons meaning keeping it consistent, I monitor the ball position, and how much if any the shaft is leaning forward at address. I try to keep my angle of attack the same and the amount of shaft lean at impact consistent. To go higher or lower, I move the ball up for higher, or back for lower a small amount. I’ll have the weight little more forward for lower shots or back for higher shots at address. To really keep it low I’ll finish lower and to really hit it high I’ll finish higher up.