I was taught stalking by an old bowhunter that said, if you want to learn to move quietly in a forest, you must believe that you can become part of the forest. Meaning, look like part of the tree when you're standing still and if you make noise when moving, make it sound like part of the natural sounds of the area.
Also, it helps in the beginning to remove your shoes and socks. It teaches you to slow way down and feel with your eyes and then your tender feet, before putting the foot down. Whether or not you place your heal or ball down first probably doesn't matter, except for balance, but the principle of each is to put as little foot on the ground as possible until your weight is shifted and settled.
Sometimes it's an advantage to make noise in a noisy woods. If you sit quietly and listen to the critters that live there, they can be quite noisy as they go about their daily activities. Mimmicking those sounds will sometimes aid your stealth. Just knowing when and when not to make noise, move, etc., is most of what you'll need to learn.
Moving when you can see the eyes of your intended prey or a human is a dead bust. Most animals and humans zoom right in on even the slightest movement. Breathing into the belly instead of the chest will help to quiet you and even though breathing may not carry very far for humans to hear, a deer will hear your breath from a 100 meters or better. Never make eye contact, because once you do, it's all over. Cover your hands and the shine on your face. They are what will be seen first. Camo isn't always necessary, if the clothing you wear blends with the coloration of the surroundings (human) and breaks up your outline (animal). If you are stalking animals, your scent will give you away. Not only is it carried on the winds, but thermals come into play as well. Meaning, early, when it cool and the sun isn't full up, the thermals will drift down, but when the air temperature starts to warm, the thermals start to move upwards.
Humans are fairly easy to stalk up on, animals can be a real challenge, especially deer and other large game. I used to take a camera with me when I practiced and would sneak up as close as I could on rabbits and other small game to learn the art of stalking. Got some really nice photos too.
All life is subject to the laws of Nature, or to be more precise, the laws of our CREATOR.