Correct inefficiencies in one limb by changing the mechanics of the opposite limb.
One of the simple aspects of running is that the upper limbs (femur and humerus) must be moved in opposition to each other. If one side is passive, the other side will also be passive. This provides another strategy in correcting inefficient mechanics.
For example, the right leg may not have a complete pull on the ground during the drive phase. The first correction to try is changing it directly by trying harder. This may not work if the left leg has the wrong mechanics. The left leg may not be driving forward long and hard enough to get a full forward rotation of the thigh. A short forward rotation and early activation of the glutes on the left leg will require an early activation of the hip flexor in the right leg, thus shortening the pull with the right leg. By focusing on driving the left knee forward, the right leg can complete its backward rotation and complete its pull on the ground.
Another example is found in the glutes not activating early when the knee is high in front of the body. The first correction is to focus on activating the glutes early. If this doesn’t work, the problem may be due to a passive hip flexor and hamstring in the left leg. If the left leg is passive, the right leg will also be passive. Try activating the hamstring and hip flexor of the left leg to allow the right glutes to activate earlier. This is also what creates scissoring before ground contact.