Take off running shoes, socks or barefoot - converse/vans if you must.

Start doing dead stop/full reset reps. It'll help you improve your technique immensely.

Neutral spine (neck). Don't look up and initiate with your eyes locked in the mirror.

Think about using your arms as hooks/chains, pulling your lats down into your hips/pockets, and driving your feet through the floor (like you're literally trying to push through a wooden board beneath you) to initiate the lift by squeezing your glutes as you initiate force. Imagine your body is the spine of a book, you're looking to hinge from the hips rather than squatting the weight as you currently are.

Keep the bar against your shins. Don't let it dip in front of you, especially on the way down. It's normal for it to hurt, for you to bleed, bruise, etc. - this means you're doing it right.