My thoughts on this have been evolving towards T3hPwnisher's line of thought, although I have yet to enter a meet.
Tonight I hit a squat of 415 for 4 with no belt and very loose wraps, which I was quite pleased with. I did the same thing I did for the prior set of 375x3. Spend some time breathing deep, swing back and forth on the bar for a few seconds, un-rack, two steps out, plant feet, get my air, get tight, squat, get my air, get tight, squat, repeat.
Generally speaking, I've had success with shortening the steps I take prior to the lift as much as I can, and I intend on continuing that trend. I used to jump around, slap my face, shake my head, make odd noises, all kinds of stuff. Now I just focus on getting my air and getting tight without much fanfare.
I run 5/3/1 and my top set is just another set, albeit one I try to find my limit on. I don't know if "psyching up" will give me another gear or not, nor do I really care much at this point. I am just interested in normalizing my mental state to lift with confidence and consistency. The weight I lift is the weight I lift and I don't want to let myself be intimidated by any of my sets.
This has been successful for me, insomuch as I've always been able to duplicate or exceed past efforts.