Clothes make the man.
Dress for success.
These axioms contain truth. As the Sefer HaChinuch famously writes, a person is influenced by his own actions. If a truly rotten individual decides to behave like a tzaddik, spending his days learning Torah and performing mitzvos, even if he does so for ulterior motives, he will eventually become good. The converse is also true. If a truly good person is forced to do bad things - say, the government coerces him to take a job that involves cruelty - he eventually will become cruel. Such is the effect of our behavior.
Why is this relevant?
Chazal tell us that a person should repair his aveiros with the very limb that performed them. Accordingly, Rabbeinu Yonah writes that if person looked at ervah and corrupted his eyes, he should repair the damage by teaching himself to look down as he walks. The Reishis Chochmah points out, however, that this is not just about practical considerations, that by looking down one avoids seeing improper things. Rather, looking down engenders feelings of humility, and humility leads to yiras Shamayim, which prevents him from sinning.
The Shevet Mussar writes that if one who is walking sees women walking toward him he should look down. Don’t argue, he adds, that it is only a glance, for if it were so, why is the yetzer hara pushing him to continue to look?!
Similarly, the sefarim suggest that when going outside, a person should train himself not to look around. Even if he is seeking someone, he should not survey his surroundings but should rather rely on Hashem to send him the person he is seeking.
Now, you may be thinking, “There is no way I can do this. I am not the type to look at the floor when I walk, or when I see someone approaching. I would feel like a total fraud. This is only for the really holy type.”
You’re right of course ... but the only difference between you and the holy type is what they do, not how they think of themselves.
Look down, look away, and presto - you too will be the holy one, for as the Chinuch writes: “You become what you do” [and you will come to terms with that too]!