1) Your life's focus must always be on the positive. You absolutely can't go around the whole day concentrating on what you're not going to do. Someone who does that is simply not living, and of course it can't work. The first thing is to make sure you know what you are trying to do with your life and then you can concentrate on accomplishing that goal and starting to really live. When you think of guarding your eyes as a means of getting where you want to in life, you won't have that problem. It's tested and proven.
2) R' Avigdor Miller zt'l said that shmiras einayim is pointless, if you are not also guarding your thoughts.
3) The mind set has to be that it's all a bunch of nothing and stupidity. Not guarding your eyes allows the menuval to get in and make something out of nothing. But if you think "It's paradise out there but I'm not looking" then you're doomed to failure.
Just wanted to share something I saw in the Michtav M'Eliyahu from Rabbi Dessler z"l.
Chazal tell us that "im puga buch menuval ze, mashcheyhu l'bais medresh" (If you encounter this 'mevuval', drag him to the bais medresh). Rabbi Dessler is medayak in the lashon of this statement and asks ... why does it say if you encounter this 'menuval'. It should say if you encounter the yetzer hara, drag him to the bais medresh.
Rabbi Dessler goes on to explain that in order to fight the yetzer hara, you must first realize that he is a 'menuval'. Rabbi Dessler elaborates that the yetzer is "oseh meseh nivlus" (performs actions of nivlus). The yetzer promises a person that he will bring them satisfaction and contentment, but leaves them only with sorrow and despair. There is no bigger Nivlus than that.
Never let the Yetzer Hara convince you that this struggle is too hard for you, or that Hashem didn't give you the strength or the tools or the nature to be able to over come him. Human beings are capable of the most amazing things when they put their minds to it. For a strong example of this, click here. (By the way, it's not a Chr-stian song, see here)