Rather than trying to touch the bar to your chest or reaching your chin over the bar (both of which can produce dysfunctional mechanics), the goal should be to achieve proper upper back and lat activation. This requires several components.
Instead of my usual Q & A column this month, I'm going to get a few things off my chest. Don't worry though, it won't simply be the ranting of a dieting bodybuilder; you'll probably learn a few helpful things along the way, too!