Step 1: Clothing.
For shoes you want light, comfortable shoes with a soft sole. The best suited would be water shoes. They are cheap, incredibly stealthy, good for swimming (who would have guessed) and way easy to get.
For pants a light, tight fitting pair made from a natural fabric is best, such as wool. To test whether you're clothing is good or not, rub the fabric against itself. If it is loud, don't use them if it isn't then great.
Step 2: The First Step.
Start by stepping lightly on the outside of your foot near the back. Now roll from there to the inside of the ball of your foot. Keep practicing with it and soon you will be able to run along concrete creating no sound (to the human ear)
Step 3: The Second Step.
Step down lightly with the ball of your right foot. Let all the weight lie on your left foot. Now slowly start to transfer the weight onto your right foot. Repeat for the left foot.
Start slow and work on stealth. Don't go for speed. That comes later.
Step 4: The Third Step.
This is by far the hardest step to master of those i've shown you. Generally avoid these areas as even masters in this technique cannot cover these areas completely without sound and even then it is slow moving.
The thing to this technique is to step down with all the weight equally distibuted, flat footed. Try also to reduce the contact sound (if you don't know what that is Im not going to explain it to you, you're ignorance shall be your downfall MWAHAHAHAHAHAHAHAHA!!!!!!!!)
Step 5: Tips.
If someone hears - stop and listen to see if you've been discovered. If not, continue but be wary as continued noise will become suspicious.
Don't disrupt nature - you may be the most fleet footed human being on the planet but if someone hears say a bird get really alarmed and fly away as quick as they can, that person is going to know somethings knot right.
Try and avoid - trouble areas such as gravel. Surely you could find another way?