Eyes ahead and bar tight against your back.

Feet about shoulder width apart with feet pointed out slightly. Weight in your heels .

Engage the squat with your butt.  Actively pulling your butt to your heels.

Controlled pull on the way down, make sure that your butt is below your knees.

Drive through your heels and finish with your hips though the top.

At all times push your knees out over your toes, not allowing your knees to dive in, and you should always be able to wiggle your toes in the squat.