I know its been answered, but I just remember it by whichever way you turn when you change the rein! When you are in the centre of the school just walk towards the track. Whichever way you go is that rein! If you reach the track and turn left you are on the left rein and visa versa. But I can't really talk, I don't know my lefts and rights when I'm driving. Mental block, dunno why!