To hit a draw, you could strengthen your grip, close your stance, move the ball back, swing out to the right, and do any number of other things that we've been told will help hit a draw. Same thing for a fade (except the reverse). But I've found that these methods sometimes have too many variables and don't always end up giving us the shot shape intended; sometimes the ball hooks wildly instead of mildly drawing, slicing instead of mildly fading, or ironically going straight! Being able to shape the ball is important in order to advance in skill. Shaping the shot allows one to bend the ball around obstacles, fight the wind's influence, reach a tucked pin, control trajectory, control roll upon landing, and generally avoid trouble.
I think Jack's method (being taught in the video below to beginning children of the First Tee program) might be the one to use because of its simplicity. Jack Nicklaus advocates using the same swing for all shots. What he changes is the club face and maybe the ball position. In other words, he loosens his normal, neutral grip, opens or hoods the club face slightly (depending on the desired shot shape), and then regrips with the same neutral grip. However, keep in mind the caveats below.
Many instructors correctly advocate creating a divergence between club face and swing path to shape shots, but they often are nebulous in their explanations (i.e., "aim your club face at the target and swing either left or right of the target"). However, one must either change the grip on the club (i.e., stronger or weaker), change the club face position at setup (as Jack describes), or use the hands/arms to control the club face during the swing. Simply "aiming the club face" with no other modifications will do nothing except cause one to lose another ball. Actively rolling the forearms (closing the face for a draw) or blocking the forearms (slowing the face for a fade) is a method best left to the timing of professionals.
Here are my embellishments to Jack's simple method. Stand behind the ball and pick a desired target. Set up on that target line as if you were going to attempt to hit a perfectly straight ball. To hit a draw, hood or close the club face a few degrees as described above (ungrip and regrip the club to do this). Now adjust the body and stance such that the newly hooded club face is aimed at the desired starting line (i.e., for a draw, aim the face and body further right of the target line). Now take a normal swing as if you were trying to hit the ball well to the right of the target. The ball flight should start right (where the club face was aiming at address) and draw or turn back towards the intended target.
For a fade, reverse every step above; you should ungrip, open the club face a few degrees, and then regrip. Aim the body, stance, and club face left of the target line and take the swing as if you were trying to hit the ball well left of the target. The ball flight should start left and fade back to the right. Use the exact same swing for both. We're following Jack's advice by reducing variables and making the swing simpler.
Now a few caveats. When attempting a fade, go with at least one club of lesser loft (e.g., 5-iron instead of 6-iron) for the required distance; this is because the fade shot will tend to go higher, shorter, and land softer, with little or no roll. The opposite is true for a draw: it will tend to go lower, longer, and run after landing, so choose a club with more loft for the required distance (e.g., 8-iron instead of a 7-iron). When you open a club you're adding loft and taking away loft when you close a club (closing down a 3-iron will turn it into a 2-iron or less).
Also, clubs with lower lofts (like a driver) don't need to be opened or closed quite as much to impart the same amount of side spin as higher lofts (like a pitching wedge). So you should hood or open clubs with lower lofts (e.g., driver or 4-iron) much less than you would with higher lofted clubs (e.g., 8-iron or wedges). As always, experiment!
Next, close your face a bit at address. But be careful not to close too much. Drivers don't have much loft so if you close the face too much, you can't get the ball airborne and lose the distance.
Then all you do to play a fade is aim your body slightly left (as Jim is making sure I'm doing above), open the clubface, and make the exact same swing.
You are starting the ball to the left because you aimed your whole body to the left. In other words, you are purposely trying to hit the ball left of your target. In trying to teach this shot to people this is where they go wrong. They aim there stance and body to the left yet they swing down the target line. REMEMBER: if you aim left, you have to swing left. The ball will spin right because of the clubface position.
In order to hit fades and draws or to hit the ball low or high, Nicklaus uses the same swing. It is the angle of the club head at impact that enables you to hit these variations in your shots. To get the club head on these angles, Nicklaus simply adjusts the position of the club head at address.