With irons I am working on not coming over the top. With the driver being a longer club (and me being about 5'-9") the swing plane is flatter and it is much easier for me to come from the inside. So I tend to draw the ball if I am coming from the inside or pull it if I get over the top. My preferred shot shape is to start the ball down the right side and draw it to the middle of the fairway. I have a target line where I focus on a spot several feet in front of the ball.
If after contact I see the ball fading to the right, I have made the connection that I forgot to focus on my target. So somewhere between my take-away, backswing and down swing, my mind wandered and I lost sight of my target point in from of the ball.
I have also made the observation that if right before impact I have that target point on my mind then I have the clubface in a good position to keep the ball in or near the fairway. So to me it comes down to concentration. In my youth I would just swing at it and wondered why it usually faded or sliced.