Its a well known and obvious fact that when a surface faces the sun it is exposed to more light. Tracking the sun with a solar panel gives you up to 35% or more power over a similar sized fixed installation. But the motors to make this happen impose extra costs.
In the natural world, plants have evolved to follow the sun. So could we artificially mimic a sunflower and use this to point solar panels at the sun? MIT has demonstrated just such a system using a curved arch made from two different metals. Simple systems like this should be cheap and the techniques, known as biomimicry, have many applications beyond just tracking the sun.