First and foremost: you need to keep the damn bar against your legs.
I had my form recorded today doing 235lbs, but it felt off. I feel like I can lift a lot more if I can just keep my back correctly flat, but it's tough because of my poor flexibility. I have HORRIBLE thoracic and hip mobility, but I'm working on fixing it.
Any other tips because at this point, I feel like I'm gonna injure myself if I go heavier.
Video:
http://youtu.be/-1azqqDKISQ
First and foremost: you need to keep the damn bar against your legs.
Yeah, that's something I have to work on. Anything else?
The bar is over middle third of the foot. Where should it be?
Also, keep your chest up at the beginning through to the end of the descent. Your back collapses into flexion on the way down. Though the eccentric portion of the deadlift is not the emphasis of the lift, maintain tightness and good form anyway.