Secret #1: Get your stance out wide!
If you squat with a close stance, move your feet out. If you think you squat wide already, move your feet further out! We teach everyone at Westside to squat wide. We don't believe in a close-stance squatter. When you squat wide you create better leverages for the squat. The distance between your knee and hip is greater with a close stance, thus a longer and more difficult squat.
By using a wide squat you cut this distance back as well as place the emphasis on the glutes, hamstrings and lower back. These are the muscles that squat big weights! While squatting wide, try to keep your toes straight ahead or slightly turned out. This will create a tremendous amount of tension in the hips and glutes and make it hard to squat down. This tension will create a great stretch reflex out of the bottom of the squat. This is vital to the development of barbell speed.