Excellent post, Grimmer! I could not agree with you more about arching the back as hard as possible and sitting back when box squatting. This post is a great reminder for all of us to really focus on technique. It's much too easy to go to the gym and "go through the motions" without focusing on the real goals - increasing strength & perfecting technique.
I also try to break down each lift into steps and visualize in my head how the lift is going to be performed. When I perform the lift I run through the steps in my mind as I actually perform the lift. Focus on a few basic lift Performance
steps (i.e. squatting - set the weight, strong arch, big air, sit back, get to depth, explode out of the hole, head & shoulders lead, knees out, break the bar, hips forward, set the weight). Now, this is quite a few steps and each will have their own personal weaknesses and these personal weaknesses should be the focus for each respective lifter. The key to this technique is to use it each and every time you perform the lift. It is similar to a golfers or baseball players pre-swing routine. If you use the technique when performing warm-up sets then it will become second nature. This becomes important when using maximal weights because the mind tends to become focused on only functioning with the central nervous system to fire muscle fiber maximally. This is why many lifters describe maximal lifts as mind-clearing. You don't know what the hell was going through your mind; the only thing that mattered was lifting that steel. I know personally that when I have thoughts running through my mind as I lift, (i.e. Do I need to get a bigger singlet? This one sure is tight. - Dumb, like that.) I never have my best attempts.
Grimmer, great start to a thread that everyone can benefit from.