No matter how you look at it, deadlifts are more about moving your hips than your lower back. We've stressed the importance of the "hip hinge", but since it can be tricky to learn, here's an easy drill to help you master the pattern. The tricky part is learning to move your hips without flexing your low back. This drill is best with a set of resistance bands, like the TRX trainer or other less expensive suspension straps. Push your butt back with your hips, while holding onto the straps to help you keep your back straight. This lets you get a "feel" of the hip hinge and stretch your entire upper back and shoulders, making this drill a great warm-up, too. Then thrust your hips forward to get back into position.
Alternatively, if you don't have suspension trainers, this video by Tony Gentilcore demonstrates another drill that also helps you keep your spine neutral throughout the hip hinge.
A broomstick or long ruler instead of the dowel rod works, too.
TRX Hip Hinge [Modern Manual Therapy]