First things first, when you approach a loaded barbell. Make the decision to be there!
This is not the time to stroll up, ease yourself into position and fart around. It doesn’t matter if it is your warm up or a new 1RM. (By the way, this applies to all lifts, not just the Squat)
Mentally psych yourself up to lift the weight. Get excited, be pumped, jump around, grunt, yell, or maybe let Travis slap you. If you’re not a yeller go to that quiet place of absolute certainty inside yourself. Whatever it is, experiment with this.
You need to develop a mental intensity and focus. As strong as you are, if you are not mentally prepared to own the barbell, the barbell will win every time. PS. I Bet you’re a yellerl
Check out this video of Rosanna setting up for a Squat. Pay close attention to her routine. http://youtu.be/74aKNVeoRgI