In the Wilderness
As you might realize, the problem with this rule is that predators have excellent senses of smell, which is why they are predators. However, predators may not be the only things that can attack you. Think about it more and you’ll see that you might face native tribes. There are two possibilities when encountering a tribe. The first is that they’ll be surprised to see a human with blonde hair and blue eyes. They’d like to keep you as their guest and learn more about your culture. They could even mistake you for a god. On the other hand, they could mistake you for a weirdo and think that you are an enemy from a rival tribe. Worse still, the tribe might still engage in cannibalism. So you must be able to practice breathing underwater or in mud (this takes a ton of time and effort), unless you are in a dry habitat. You could also gather twigs from trees and use them as a covering, and when you really need it, jump into a thick bush. Camouflage drastically increases your chances of surviving regarding native tribes.
In School
Want to be as stealthy as a Ninja? Then I suggest you think about camouflage. But where in the school can you find camouflage if you accidentally piss off the school bully? For beginners, it’s best to go into the restroom. This is more effective if you’re the opposite sex as the bully. But even if not, when a toilet stall is occupied, the bully will most likely leave. In the worst-case situation, the bully could go into the toilet next to you and then climb over the wall to get you. For professionals, I’d suggest a locker. This requires practice but it’s more effective. It is real stealth. When a bully is chasing you down, you’ll need to make sure that both of you are at quite a distance from your locker. If you are close to the locker, he could lock you up in there and you’d never get out. Make sure it’s open in advance (if someone tries to search your locker it’s not my fault because I’ve warned you that this is for professionals only). And you’ll need to practice hopping into the locker followed by the “quick-pull”, an advanced technique few have achieved that consists of pulling the locker door from inside at a tremendous speed to make sure the bully doesn’t know you are in there. Don’t try to run into a hallway crowd though, unless you’re thin enough.