When you get to a certain point in your shot sequence, you just have to create a check on your checklist that now is the time to really focus on the spot you want to hit. For me, using the Rick Welch method, it would be during the 2 second hold, after I have rechecked my alignment and made sure my string hand and forearm is relaxed.
Are you going to forget to do it? Sure. Just like I forget over and over again to follow through. But I guess if you are at the point where you are aware of when you forget to do it, like I am with forgetting to follow through, then at least that's better than missing and having no idea why.