9. Hip Drive
When you hit the bottom of the squat (i.e., hip crease below the top of your patella), drive your hips up. Don’t think about driving your chest up. Drive your hips, and because you locked your back in rigid extension using tip #5, your chest and the bar will come up with your hips.
10. Stay in Your Lean
Stay leaned over a little longer than you think. You will “get vertical” eventually, i.e., your back angle will eventually become vertical (since you finish the squat in an upright position), but don’t try to get vertical right away as this makes makes for a weaker, harder, less efficient squat.
Stay in your lean.