Guarding your eyes starts internally with guarding your mind. Triggers only harm us if we haven't trained our minds to do what we want. Just as triggers trained us one way, we can reprogram and train our minds to react in a different way. Sometimes it doesn't seem that complicated. Sure, seeing something sets you off, but what the switch actually does is for ME to decide. Personally, I'm going to insist to my own brain that seeing someone doesn't have to mean anything it to me. It's all about perception. So there is a human being that looks a certain way in front of me. Now what? It's irrelevant to me. Am I going to react, keep looking and/or let my mind get carried away? No. I choose instead to be in charge, to turn to Hashem, to focus on anything else, to not dwell on it. Our brains don't know much besides for what we tell it, and I'm telling mine that there's a lot better stuff going on elsewhere. And I'm not even kidding myself, it's absolutely true.