The ball can be placed anywhere from the inside of the front foot to the inside of the right foot. (right handers). This is a very loose piece of information. However, you will have to work out which position is best for you. Some Professionals advocate moving the ball back in your stance for the shorter irons. As the irons become shorter, so the ball moves back in the stance.

I hate this. I believe that one position is right for every shot you make. Moving your ball around in your stance leads to inconsistency and errors in the golf swing. I hit too many fat shots when the ball is not in the correct position for me. When it is where I like it most,I never hit a fat shot. Find your spot and you will not hit one either. The orthodox position is just inside the left heel. (The left foot points slightly towards the target). This is a long way forward, and I believe it leads to all sorts of problems. You really have to keep the club moving along the path of the flight of the ball. It is easy to hit a fat shot when the ball is positioned here. It is also very easy to hook or slice from here. Especially if you are a little tired.

When you are tired, the swing is not quite along the correct plane and it can become shortened resulting in a hook or slice. Experiment and bring the ball back towards your right foot bit by bit. To help you find the right position, swing your club and see where it hits the ground in relation to your stance. Then put the ball here and see how it feels. If you have it back towards your right foot, you will be given all sorts of advice about steepness of down swing etc. Take no notice, and if the position suits you, stick to it. Find the spot where contact with the ball is sweetest, and where most accurate results are achieved.

Find the spot where you can hit down on the ball most easily. Most if not all good players, hit down on the ball and pinch it between the club and the ground. This will give you more accuracy and your shots will be longer.