Performing a structured scan (e.g. checking the manoeuvring area, then the strip bay, then the A-SMGCS, etc. before issuing a clearance) helps ensure that no conflicting clearances are issued and to confirm that all clearances are properly complied with.
A thorough scan of the manoeuvring area during or prior takeover mitigates the risk of previous controller failing to properly hand over the working position.
Use of memory aids may help mitigate the risk of forgetting issued clearances.
Maintaining situational awareness at all times is an important prerequisite to safe and smooth operations. If direct observation is not possible, other methods and tools should be used to monitor the obscured areas (e.g. cameras, surveillance systems, etc.).
Compliance with taxi instructions should be closely monitored and assistance is to be provided especially if the crew appears to be unfamiliar with the aerodrome or there is an unintuitive procedure established.
As a general rule if there is a doubt that a certain instruction could be misinterpreted (e.g. for instance hesitance is detected during the crew readback) or a doubt exists about the possible crew intention, the controller should be proactive to resolve in unambiguous way the possible areas of concern particularly if there are precursors that misunderstanding could arise.
Whenever possible, runway entering/crossing clearances should be issued separately (e.g. the aircraft/vehicle is first cleared to the holding point and the runway clearance is issued only after there is a reasonable certainty that it is safe to cross or enter the runway). This also mitigates the risk of communication loss.
It is preferable to confirm (either visually or using surveillance) that the aircraft/vehicle is approaching the intended holding point before issuing a line up or clearance to enter/cross the runway. This helps mitigate the risk of runway incursion and should be used whenever practicable as workload permits.
It is preferable to confirm (either visually or using surveillance) that the aircraft has lined up on the correct runway before issuing a take-off clearance. This helps mitigate the risk of a take-off roll commencing from a wrong runway or a taxiway and should be used whenever practicable and as workload permits.
The issuing of “a time-block clearance” to vehicles (sometimes used at less busy aerodromes, e.g. “Cleared to cross runways/taxiways for the next 60 minutes”) should be avoided. Each vehicle movement on the manoeuvring area should be subject to a separate clearance and the runway/taxiways should be marked as occupied according to the local procedures.
The level of familiarity of some crews could be low about certain airports, particularly if it has a complex layout (or closed taxiways due construction work, recent change in the taxiway layout/signage), the controllers should be prepared to provide progressive taxi instructions.