The position of the club in the pitching finish is a great rehearsal for where the club should be after impact on your full shots. In both cases, for the swing to be on plane, the shaft should be pointing at the target line and the clubhead should be slightly inside the target line. When the shaft and clubhead point outside the target line, you've made an inside-to-out swing and likely either hooked or blocked the shot. When the clubhead is inside, you've swung out-to-in and sliced or pulled.
Turn your body with the club
The impulse to hit the ball--and not swing through it--makes a lot of amateurs move the club with their arms only. But just like on a pitch shot, the body motion propels the club through impact on a full swing.This hinge-and-hold pitching drill helps ingrain body motion and the hinging needed with any club. Grip a wedge about mid-shaft and make a backswing as if you're pitching (remember to hinge your wrists). Now swing down over the top of an imaginary ball. The object is to keep the butt end of the club from hitting your body. Do this by continuing your body motion while not unhinging your lead wrist. Keep your body moving!