In creating forward momentum, that is the acceleration of the body weight in a forward direction, the first movement that must occur is the bending of the ankle. In bending the ankle, the hips and center of gravity will accelerate forward.
On of the most common errors we see is hip dipping, or lowering the hips rather than bending the ankle. In other words, you reduce the angle between the shin and the thigh (bending the knee), rather than reducing the angle between the top of the foot and the shin (ankle bend).
Although it is OK to reduce the knee bend very slightly in loading the push, there is a point where you can reduce it too much and the weight accelerates back to the heel, rather than forward to the ball. Although you may feel you still have a powerful push you will be missing the added momentum from the acceleration of body weight forward. The primary focus of load MUST be on the ankle bend, with the knee angle staying in the same position during the load. In other words, if your knee angle is at 100 degrees at the start of the loading phase, it must remain at 100 degrees until the ankle is fully loaded, you have maximum pressure under the ball of the foot, you are at the point of instability, ready to explode.
There is also a point where you can, believe it or not, be too low. Stand with both feet pointing straight ahead and about shoulder width apart. Bend at the waist so that the back is about 45 degrees to the floor. Bend the ankles so that you feel the weight is on the ball of the foot. Now slowly bend the knees, lowering your hips down. As soon as you feel the pressure start to move backward toward the heel again, you are TOO LOW and will not be able to accelerate the weight to the ball of the foot. So now, find the spot where you the ankles are compressed such that you have pressure on the ball of the foot, lower your hips until the weight starts to move backward, then raise them to the spot where you have pressure on the ball and THAT should be the best skating position for you. Of course, if this creates a knee angle that is above 105 - 110 degrees, you probably need to work on your flexibility.