The Mistake: Not dropping down low enough.
The Fix: Take a slightly wider stance, which allows the body to stay steady while it squats deeper, and engages more muscle groups. It’s easy to want to squat just low enough so the thighs are parallel with the ground, but squats can be much more effective when we drop as low as possible (the hip joint lower than the knee joint) while still maintaining good form.
The Mistake: The knees drift inward.
The Fix: Turn the toes out (between 5 and 20 degrees) to keep knees from caving inward. Knees should track in line with both the ankles and the hips, to help avoid injury and get deep in the squat. Glute bridges and lying clams will help knees from caving.
The Mistake: The body leans too far forward.
The Fix: Put most of your weight in the heels when lowering into a squat. The weight distribution will help keep the torso upright through the squat rather than teetering forward, and help keep the hips back and down, outside of the heels. Try to spread the floor apart by driving outwards through the back/outer portion of the heel.
The Mistake: Descending too quickly.
The Fix: When weight is added, moving too quickly could increase chances of injury. It’s okay to explode with power when returning to standing (so long as the body remains controlled), but sitting into the squat should be a little slower to maintain proper form.
The Mistake: Not warming up.
The Fix: Before squatting up a storm, try glute bridges to open up hips (which will allow the body to get lower in a squat). Warming up is important before taking on such a complex move. It’ll help prepare the body’s joints and muscles for movement, and might even help prevent injury once heavy lifting get underway.