Foreword-I’m writing this from my phone, so please excuse any auto-corrects that pop up.
The most common technical mistake I see with squatting is the movement initiating at the knees, forcing a wierd looking movement that includes the heels rising off the floor, knees way over the toes, and a severe lack of depth.
Besides looking like a fool this poor technique is unsafe due to poor balance, increased stress on the knee due to valgus collapse and anterior weight shift, and less effective due to decreased muscle recruitment.
To fix this try one of two things.
First, push your hips back as if sitting into a chair. This will even out the weight balance as well as recruit the hamstrings and g lutes while allowing for greater depth.
Second, spread the knees apart, allowing them to track over the knees and recruit the posterior chain optimally. This also allows better depth and a safer squat.
Take these two tips to better your form and squat more efficiently, bam!!