When it comes to Shemiras Ainayim outside in the street, we have to realize that EVEN WHEN WE LOOK, the pretty girl is gone in a moment, AND WHAT DID WE GAIN? NOTHING!!! Adarabah, what we LOST was tremendous, cuz we wired our brain at that moment, we conditioned ourselves to want to look, to give into our taivos all the more. Next time will be harder to avoid, not easier, and maybe a bigger slip, or it might be the straw that breaks our resolve for good, chas v'shalom!!
And remember something else, guys - you know you've felt this: Even after you look, five seconds later she's gone from view, you've forgotten about her anyway, she means nothing to you anymore. So instead of looking, you can keep from looking until she's past and it's no longer possible, and then you realize YOU LOST NOTHING. BUT YOU GAINED ETERNITY!!
Now, take it up a notch and apply the same method to viewing porn & acting out. If the urge comes, GET AWAY FROM THE SCREEN and the opportunity to peak easily. RUN AWAY!! Get involved in something else, get your head out of it. Call a friend or a sponsor! AND SCREAM OUT TO HASHEM RIGHT THEN - "SAVE ME!!" - You'll see that after a few moments the urge should lessen, if not disappear completely for the time being.
And then you'll realize, by NOT looking, by NOT doing, you didn't really miss or lose anything. Cuz then you see that it means nothing to you anyway. And you'll realize WHAT YOU GAINED!!