Each of the leg exercises listed should be performed with proper form to not only avoid injury, but to also allow the muscle to go through a full range of motion and get the most out of the exercise.
1. In a squat rack, take a barbell off of the rack by placing it squarely on your traps and shoulders (not the neck) and grip the bar comfortably with your hands a little wider than your shoulders.
2. Carefully take a step or 2 back from the rack and get in a comfortable upright stance with your feet shoulder width apart or slightly wider. Your toes should be pointed slightly outward. They should NEVER be pointed inward.
3. Focus your vision on something straight ahead and slightly above you. Do not tilt your head backwards, downwards or to the sides as this will disrupt your balance.