Considering the D-Plane and "new" ball flight laws, try this method to set up for your draw or fade. It's very similar to the way Nicklaus and Watson (see Lesson 1 Lesson 2 on youtube) set up to shape their shots.
GC: What about the pre-shot routine; is that something you think is important?
TW: I talked about the target line and aiming. That’s your pre-shot routine; if you can do that, that’s fine. Getting behind the ball and hitting that ball over a point like Nicklaus does, that’s all the pre-shot routine you need.
You’ve got to aim it with the club face. You’ve got to learn how to do that; a beginner has no clue. “Where do I aim it? Is the club face square?” How do you determine whether the club face is square? You see people play with a closed club face and an open club face. But then they make an adjustment in their swing to try to get their club face back to square.
I call it "holding off the shot." I'm keeping my arms quiet with far less forearm rotation and delaying the closing of the clubface. I think of it as squaring the face with my body rotation. You can see here my hips have turned significantly toward the target before the club has reached the ball. That's a good fade feel for me.
So you can see (in harmony with the "new" ball flight laws), Tom Watson understands that the club face should aim where you want the ball to start…not where you want the ball to end up! If he has a natural hook in his swing, he needs to aim right to bring the ball back to target. This is why most pro golfers you watch on television appear to be hitting the ball off to the right; they're drawing the ball back to the target.
Stand behind the ball and imagine the TARGET LINE--a straight line from the ball to where you want the ball to carry. Don't worry if some obstacle falls on this line (e.g., a tree, trap, or dogleg); your intention may be to use the curve to go around that obstacle! At the same time, imagine an AIM LINE--a straight line where you want the ball's flight to begin. I recommend starting with smaller curves, so the aim line should be relatively close to the target line. These two lines (if imagined to be infinite) will intersect at some point behind you, forming a small angle.
The best way to create these lines at setup is to pick two points on the ground a few feet away from the ball; use blades of grass, broken tees, and so on as the points on the line. You'll need these frames of reference for alignment. I never pick points on these lines that are more than 5 or 6 inches aways from each other.
Set the club down with the face pointing down the aim line (not the target line); in other words, point the face at that spot chosen on the ground. If you find yourself hitting pushes or pulls instead of draws or fades, try closing or opening the club face slightly, but NOT at the target line. Now, align the body slightly open to the left or closed to the right of the aim line, depending on which curve you're attempting to produce. Putting the ball back in the stance slightly will also encourage a draw or hook, and vice-versa for a fade, slice, or cut; I advise, when using the ball position in this way, to simply align parallel to the aim line the way Watson recommends.
If you don't use the aim line and close the club face coming through, you may hook the ball off the course (same with a fade--ball slicing off the course--if you don't adjust your alignment to the left).
In essence, the infinite, imaginary aim and target lines along with the line created by the setup (i.e., TOE LINE - imagine a straight line running from the toes of each foot) will intersect at some point behind you and the distances between those lines will increase gradually as they proceed toward the target. Once you've addressed the ball, forget the target line…concentrate on the aim line (where the club face is aiming) and swing either left of it for a fade or right of it for a draw. These are feels but in reality you can use an inside-out swing for BOTH (remember…it's the club face relative to the path that imparts spin).
As alluded to earlier, Watson teaches that the toe line should be parallel with the aim line; but we want to avoid hitting a straight push or pull, so I advise SLIGHTLY closing or opening the toe line to the aim line, depending on the shot shape desired (unless you use some other method for encouraging the correct swing path). Once again, these lines are only FRACTIONALLY offset from parallel, especially the toe line. If you're already adept at controlling the path of your swing, the toe line idea may not be useful to you. Also, don't forget the ball position: Forward encourages a fade and backward encourages a draw, so this alone may be enough for you to consider leaving the toe line parallel to the aim line. Also, don't forget the D-Plane: the club face must still be offset from the swing path to produce the desired shot shape.