To properly perform deadlifts, seated hamstring stretches and numerous other exercises, the hip hinge is an important action to master. With the right cuing many people learn to easily perform the action, and over time it becomes quite a natural position.
One of the images I use to help clients hip hinge properly is the "tipping bird."
I get a blank stare if I mention it to a forty-something or younger person. But if you're at least 50, you likely remember the ridiculous novelty item that was probably introduced at the same time as the pet rock.
The skinny stork-like bird slowly and stiffly tips forward in a plank-like manner from the hips toward a glass of water, and then it returns just as stiffly back up to its original position. Its head doesn't change position; there's no movement at its waist.
Because hip hinges result in a position where you're looking at the floor, checking your body alignment in a mirror isn't an option during this type of exercise. So you need a good image or two in your head (or feedback from an observer) to guide you.
The next time you're hip hinging, conjure up an image of the tipping bird. Take a preparatory breath in, and then begin to hinge forward.