Explode through the floor.

Imagine the bar is an immoveable anchor to grip while you push your feet through the floor. Extend your hips and knees in one explosive movement, dragging the barbell up your body.
Push through the floor
LIKE A UPSIDE DOWN LEG PRESS
LIKE A UPSIDE DOWN LEG PRESS
whiteboard_daily
PUSH THE FLOOR AWAY
PUSH THE FLOOR AWAY
Push your feet through the floor rather than just picking the bar up. Try creating separation between the floor and the barbell by driving your feet through the floor and trying to push the ground away from you.
Push the world away. Don't lift the bar. [People] thinking about lifting the bar end up rolling their back or they'll unravel and a cat back kind of motion... but if they keep their chest high and push the world away (almost like they're performing a leg press) things seem to go better.
Neversate
I imagine that this bar here is completely bolted to the ground. That it's not going to be able to move. So what I think about is pulling myself through the floor, and this makes me keep keep pulling and keep my back as neutral as I can so I don't rush it. I used to think about lifting the weight... trying to actually pull it up... but [now] I think about putting myself down through the floor.
Omar Isuf
PUSH THE EARTH AWAY
PUSH THE EARTH AWAY
whiteboard_daily
In my mind, I'm trying to drive my feet through the ground. I'm trying to wedge myself in between the bar and the ground and drive my heels through.
Alan Thrall
You want to think about putting force into ground and pushing away, rather than just pulling the bar off the floor. Another option is to think about "pushing the ground away from you."
When most people think about picking something up... they're thinking that they're initiating that movement at their hands...but that's not true. Instead, think about pushing the floor away. This will help you keep a much more stable and erect body position so your hips don't shoot first. Instead, you're going to be initiating your legs and your upper body is going to be trying to hold as stable as possible - almost like you're sitting in a leg press machine.
Neversate
... think of the deadlift as a standing  leg press. As I got tight, I only focused on pushing my feet through the floor. It took some practice with lighter weights, but my chest stayed up and I was able to use my legs more efficiently.
One explosive movement
ACCELERATE THROUGH THE FLOOR
ACCELERATE THROUGH THE FLOOR
THREE BEST FRIENDS
THREE BEST FRIENDS
whiteboard_daily
In a conventional deadlift, the knees and hips should lock out at the same time and what we want to see is the knee action stays forward and never recedes until the bar needs to pass it. Whenever we see those knees recede early, that means the quads are shutting off...what you want to see is when you're pulling, those knees never shift back. They always stay forward until the bar clears and the hips and knees lock out at the same time.
Brendan Tietz
You broke the inertia to get the bar off the ground, now you want to get in a hurry and speed it up... The faster that you're moving that bar, the less likely it is to get stuck at one of your sticking points. The momentum that you're creating by trying to accelerate the bar is going to continue throughout the entire lift. The absolute worst thing you can do is let that bar slow down.
Neversate
It's critical that the shoulders and hips rise at the same rate, with the bar coming off the floor.
You always have to maintain contact with the bar on the shin, and where I really wedge my hips under the bar - I aggressively pull this bar into my shins and drag it up a little bit. I don't ramp it up my quads or my shins or anything but I really make sure it's always dug into my shins. You always want to ensure we have the best leverage and that bar is always maintaining position against the shins the entire way up.
Brendan Tietz