Taking a golf lesson to the course can be a challenge. Making a swing change on the range is difficult; on the course it is even tougher. The range is the frying pan, the course is the fire. Because the golf course has many distracting obstacles, the tendency for most players is to revert back to their natural movements or habit patterns. The purpose of making a change is to hit better shots, to bring it to the course you need to have a solid routine. There are three key points to a good routine that will allow you to take your new action to the course.
First, once you have decided on the club and the shot, make a rehearsal to establish the proper feeling. Your mind may know the swing you want, however your body doesn't. A rehearsal is a motion or drill that is an exaggeration of the new move being learned and must be done on every shot. Tiger Woods never hits a shot without making some kind of motion beforehand to create a feel.
Next, stand behind the ball to pick an intermediate target and visualize the shot. The intermediate target is a spot on the ground, which could be a blade of grass, divot, old tee, etc., within a few feet of your ball. This spot helps with your aim and alignment, but can also help with your swing change. For instance, if you were a slicer (right handed) you would visualize a draw, curving right to left around the intermediate target.
Finally, commit to the swing feeling you rehearsed and the shot you visualized. Do not try to control or steer the shot. I always say, "Be willing to lose your golf ball." This means you are not afraid of the result and are more concerned with the process of hitting a good golf shot. Jump in with both feet and make the new swing motion you are learning. The more you take on this attitude the faster you will get where you want to go.