Possibly the most common mistake I see when deadlifts get heavy is the bar drifting away from the body.
Many lifters assume that a deadlift is just picking the bar straight up, but this isn't effective. As you pile on the plates, you need to think about actively engaging the lats and pulling the bar back into your body so that your weight shifts backward slightly.
Keeping the bar in tight helps ensure every pull is smooth and efficient.
"If you put a group of the most successful strength coaches in one room and their students in another, the students wouldn't agree on any training philosophy or principle, whereas the coaches would agree on almost everything."