Controlling your forearm rotation can be very difficult to see while swinging the club at 100 mph. Thus, it is very easy to through it out of sequence. Also, I find that the under standing of when the arms rotate and how much is the common issue among amateurs.
As you take the club away, your arms should be rotating right away but GRADUALLY. No jerking or throwing the club back is tolerated for that consistent swing you are looking for. And on the downswing, it starts to rotate right after you shift weight to you right side.
Well, first lets look at the full amount of rotation allowed which is 90 degrees max at the top of the swing. Thus, half way back, your forearms should have only rotated around 45 degrees and increases as the club goes back GRADUALLY. You will see a lot of pros at the end of the takeaway, when the club is parallel to the ground, have the hand directly behind or slightly out side the hands. The issue with majority of amateurs is that the arms have rotated more that 45 degrees, lets say around 60 , and now you have no idea where you club is sequenced relative to your body.
So focus on gradually rotating your forearms to control you club face and get that hole-in-one you have been waiting for.