Line Follower: can my code be optimized?

The driver is in the right bottom, the battery holder is in the middle (black) as well as a 1.5V battery at the top (two in series), the potentiometer is at the top right and the Arduino board in the top left.

The infrared sensors are at the bottom between the wheels.

Thanks so far, I realize my answers/questions were not very structured, apologies.

EDIT: Images moved to attachments