Some resources on the deadlift
Came across this Eric Cressey video on how to deadlift. The password for that video is 'deadlift'
Improving the Deadlift
Here's also a good article on the subject. This one is from elitefts.
One of the biggest things I see lifters doing wrong when deadlifting is starting in a bad position. This goes for both the sumo and conventional deadlift. First, neither style deadlift is a “leg” lift, yet many lifters try to sink their hips extremely deep to get better leg drive. Next, lifters will not get their shins close enough to the bar before beginning the pull. (Hint: If you aren’t bleeding, the bar isn’t close enough!) Lastly, the shoulders must be in proper position before beginning the pull.