RCS, or Reaction Control System, thrusters were used for manoeuvring.
Their method of operation was to eject some material, usually a gas, using the reaction (Newton's Third Law) to move the vessel. They would be positioned at multiple locations on the ship, and firing different combinations of thrusters would allow the ship to manoeuvre in all axis.
The were known to be used on the Firefly-class transport.
Real world RCS at Wikipedia - RCS