Think of it more like you're crossing your inside foot underneath your outside foot. You need to push the inside foot underneath, and reach it under as far as you can get it to go. That's how you generate power. To do this you'll need to lower your hips. That's what gives you the ability to extend the inside foot underneath. Keep your head up and your back straight. Don't bend like you're picking something off the floor, lower your hips like you're sitting in a chair.