Positioning on the deadlift is key! I thumbed through The Facebooks yesterday and saw a guy asking for advice on his deadlift. It was a near max lift and he ended up hitching the barbell at the end. Of course everyone commented "stop hitching" but not a single person told him how to do that!
1) Break PRs on Good Mornings (your worst variation) at least 8 times
2) Break PRs on GHRs at least 8 times
3) Break PRs on your abs work at least 8 times
4) Make doggone sure that your shoulders are behind the bar during the entire lift (the first 3 will take care of this with some minor technique work)
5) Make doggone sure that you have some bend left in your knees by the time the bar gets there (steps 1-4 should fix this)
Here I am working with my friend Thelma who was taught to deadlift incorrectly and we fixed it in a single session of technique work. At full speed it looks pretty much the same but when you slow it down to frames you can see the changes and why she will miss or get injured with the incorrect technique.