Hard to tell - when I coach the squat, it has to be done over a long period of time, constant interaction and honestly, apart from the usual cues, vast majority of cues are mental preparedness. By far. We focus on quality, relaxation, speed, etc. So how I coach athletes is very hands on as far as mental toughness, strength and demanding their mind is clear and strong, not some issue with toes or how their sphincter tightens.
Here's the deal - lifting weights and getting stronger gets harder and harder the stronger you get. No one tells you that since the majority of jackholes giving advice are beginners who haven't hit hard times and will invariably quit. So road blocks are going to come up and you just work around them by being smart and consistent.
The only advice I can give you without actually coaching you in person is to make sure your surrounding areas (back and abs) are strong as hell too. Set some simple standards for straight leg, hanging leg raise: 30 slow continuous reps would be bare minimum to shoot for, for example. I know it is no longer cool to be about the "core" anymore but it once again shows how trendy this business is.
We also believe in strengthening the legs/hips through sleds - because we are going after more than just a number on a barbell. So focus on those two things and bar speed.