Looking over the shoulder works. But when I was learning to fly, it was awkward for me. So I tried keeping my body facing the runway and pointing my foot in the down range direction. For example, if the plane was moving from my right to left, I would point my left foot to the left. I could mentally focus on the direction my foot was pointing while controling the plane. As I remember, the only time I really needed to do this was during landing approaches. And after a while it all became instinct.