The deadlift is one of those lifts that you can do over and over and still continue to refine your technique. I console frustrated athletes with the fact that I, even after nearly 10 years of deadlifting, am still tweaking my technique and learning to to most efficiently hoist iron.
That said, here are three cues I use on myself and with my athletes that should speed up the refinement process.
Cue: Hold pieces of paper under your arms. OR Squeeze oranges under your armpits. (Courtesy of Tony Gentilcore.)
Fixes: loose upper back
Why do we want a tight upper back? A) by creating tension in the upper back and lats, which in conjunction with the anterior core, it creates a nice "belt" around the spine and protects the lower back; b) tension throughout the back transfers force from the hips to the arms and thus the bar moves. Without it, there's a much higher risk of injury- particularly to the lower back- and the movement deteriorates rapidly.
"Squeezing oranges," which is a great external cue, cleans it right up! It's especially useful with newbie deadlifters as they may not have the body awareness to know what a tight upper back feels like yet.
Cue: Pull your chest (or sternum) to the back wall.
Fixes: Hips rising faster than the shoulders
If you or an athlete struggles with popping the hips up to soon- like the immortalized "Bend and Snap"
then this cue can help. By thinking about pulling the chest to the wall behind you, it shifts your focus from yanking your hips up to pulling your chest up, thus slowing down the hips ascent and, for most athletes I've seen, will synchronize the rise of the shoulder and chest so they move at the same rate.
Hips, above, are rising faster than the shoulders and it will quickly turn into an RDL. Below, the hips stay lower than the shoulders and the two move together.
Cue: Grab the floor with your toes
Fixs: flat feet, wiggly feet, loose feet
All of the above are unhelpful for deadlifting. Considering that the feet are the only body part in contact with the ground, wouldn't you want that contact to be stable? You can't produce maximal force while standing on an Airex Pad so why create one with your wobbly feet? Gripping the floor tightens up the foot and lower leg musculature which in turn, produces a rock solid foundation to push against.
Another boon to the cue: it breaks the habit of "toes up." (Note: I'm not 100% oppposed to the "toes up" cue, particularly when I'm teaching someone how to posteriorly weight shift for the first time. But as an athlete progresses, we pull the toes back down and teach gripping. Jarrett did a fantastic job explaining why we do that in his article. If you want to increase your lifts by 1000%, read his article linked above. Seriously, you won't regret it.)
Give those a shot and I guarantee you'll feel fantastic!