How do pilots maintain awareness of other airplanes during taxi?
At a large airport, all aircraft movements are coordinated by the ATC tower on the ground frequency. Aircraft should never move without authorization from the controller. The tower will issue instructions to aircraft that might look something like this:


  Taxi to Gate 1 via Alpha, Alpha 1, Lima 3, cross runway 24, hold short Delta.


These names correspond to markings on the ground that match up with the airport taxiing maps. By talking with the pilots, the controllers are able to build up a map of where aircraft are. It also helps that they can look out the window and see the aircraft on the ground.

At airports without a tower, taxiing isn't much of an issue. There aren't many planes around, and there's generally only one runway and not many taxiways. Nevertheless, aircraft taxiing when there is no ground controller comply with "see and be seen" by looking outside and turning on aircraft lights. Furthermore, if the aircraft has a radio, it should self-announce its movements on the ground.