HOW: Start on your back with your knees bend and slightly spread apart. Tighten up your stomach first, then your glutes. Next, drive your heels into the ground and lift your hips up towards the ceiling. At the end position your knee, hip, and shoulder should be in one straight line. Hold the end position and squeeze the glutes, then slowly return to starting position.
FEEL: You should feel your glutes work to control this motion. At no point should you feel your low back muscles doing the lifting motion. If you feel it only in your hamstrings, try bending your knees a bit more and repeat.
COMPENSATION: Avoid arching at the low back as you perform this.