[MetroMPG]

I always look for ways like this to make it easy for following drivers go around.

I think the hand motion out the window is probably the most effective one - I often use it on the rural roads I drive in combination with hugging the right side of the lane (or going on the shoulder) and signaling.

Lots of people seem to stay behind even with clear sight lines and lots of road to drive around, but the hand wave never fails. Sometimes get a "thanks" wave back too.