Some easy corrections you can make to be more fluid and efficient.
1. Squat! Do not pull with straight arms and straight legs, you need a small bend in the elbow and you need to pull yourself down by squatting and pulling down with the hamstrings and the abs.
2. Pull from just above eye or head height. Do not pull higher than a couple inches above head height, and do not pull from below eye level. Pulling from too far above head height will fatigue your arms and shoulders. Pulling from below eye level is inefficient and you are sacrificing distance and power.
3. Do not hit the stops! If you feel the cord stop you have gone too far. When you pull to the stops you end your momentum and your power. Shorten your extension just a bit and stand up before hitting the stops.
4. Do not pull straight down! Your extension should go past and behind your hips.
5. Stand up faster! If you are pacing yourself then this is where you rest, on the stand up, but if you are going for maximum speed and maximum effort you need to stand up as fast as you pull down.
6. Fix you posture! Do not bend the back, stay upright, chest up, spine straight. Fold at the waist and bend the knees, not your back!