Get your ass up a little bit, you're back is a little bit too vertical. And like Pity said, get your shoulders over the bar. The scapula should be directly over the bar. The bar should also be completely deloaded before the next pull (meaning you should stop for a couple seconds at the bottom of the lift with the bar on the ground)
To setup: Get your feet under the bar, shins about an inch away. Grab the bar with your scapula right over top of it, raise your butt up until you can get a good arch in your lower back and squeeze your glutes. Flex/Push your abs out and pull. That's how I've been doing it, maybe not in that order but that's what I remembered
Eric does a nice job of explaining it here:
http://www.bodybuilding.net/personal...lift#post54566
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