Golf power is all about generating a high "X" factor. If you watch Tiger in this YouTube link
you will see that his shoulders out turn his hips by 30% or more but then on the downswing his shoulders lag as his hips rotate and the shoulders followed by the arms lag behind. (He is obviously very athletic and is a once every 100 years type of player)
Tiger does this athletic move because his legs are very strong and he is able to anchor to the deck and create enormous tension in his right side while rotating is torso around that base.
All things being equal (and they are not), the ground base foundational moves stated here by others are the first level
. If you are deadlifting PVC and squatting the bar then start there and keep taking lessons.
Once you have developed competency in these moves I believe that you should practice some unilateral and contralateral DB moves. Along with low to high and high to low diagonal moves.
-Single leg contralateral db deadlift (see last months PMenu)
-Single leg contralateral Dball snatch
-DB Overhead Squat (lateral flexion, torso rotation)
-DB Pressing Snatch Balance
-DB Overhead Lunge Walks
-Single leg squats
Plank variations help and those bands are fine but it's going to take 3 times as long to get there.