In the Talmud (Baba Metzia 107) it says that almost all forms of death come through the agency of the Ayn ha Ra [Evil eye] and the advice to save ourselves from this is to guard our eyes from looking at forbidden things (Berachot 20) for because of this behavior, Yoseph and his descendants after him merited that Ayin ha Ra had no power over him (Shne Luchot ha Brit, Kedusha)
There is another great rule and that is not to give the Yetzer ha Ra an entrance to come and dominate you. When you are going to the public places and you look at women coming to you, put your eyes to the ground so that they pass by and you not look at them, for you will notice how your evil inclination grows within you to make you look at them, and if you don't think this is a great sin, why does the Yetzer try so hard to overpower you to the point where very few people can stand this trial, but only those who have the love of the Creator engraved in their heart. (Shevet Mussar, Chap 27)