It's also useful to understand that the balance ball doesn't actually show yaw, it shows whether your current yaw rate matches your current angle of bank.
Skidding = too much yaw for the current angle of bank.
Slipping = not enough yaw for the current angle of bank.
Coordinated = correct amount of yaw for the current angle of bank (zero yaw and zero bank when flying in a straight line).
Most of the yaw in a turn comes from the natural stability of the aircraft which maintains alignment with the airflow i.e. the fin and other vertical surfaces. The rudder provides relatively small adjustments to yaw rate.