How do I adjust all of these? Is there a way of knowing if they're out of whack? What does the actuator cable do? Does the accelerator cable control how the tranny shifts?

 

Accelerator is for the gas pedal. Throttle is for tranny. Actuator is for cruise control. If there's little to no slack in the cables compared to throttle linkage movement, your cables are fine. If the vehicle will accelerate and shift without lag time, and if the cruise control is able to maintain and regulate speed without error, they're fine. They look fine from the pic, as well.