Set-up: Set your feet wider than shoulder width, brace your core and establish a neutral spine posture.
Movement: Start the movement as if you were about to sit down, pushing your hips down and back. Descend as far as you can without excessive rounding of the back and without the knees caving inwards. Your hips should end up well below the height of your knees. At the bottom of the motion rise back up only part of the way - keeping constant tension on the muscles.
Emphasis: Focus on engaging your glutes. Do not let your knees push far forward in front of your toes or cave inward on the movement.
Assists: Holding onto a railing or sturdy door can make the exercise easier and assist in reaching deeper ranges of motion.