Listen before talking, make sure the channel is clear.
If there are other users consider an alternative channel. Either VHF 17 or 77 can be used for water sports events.
Only use enough power to do the job you need. Over a short distance (about a kilometre) low power should be more than enough, and this will cause less interference with users on other parts of the harbour. This will also increase battery life.
Think about what you want to say before you begin transmitting, keep messages short and to the point.
Speak clearly and not too fast.
Shelter the microphone from the wind, wind noise can make you very difficult to understand.
Avoid inadvertently pressing the mic’ button, including when stored, as an open mic’ prevents all other transmissions.
Use names or some sort of identification over the radio. Normal procedure is to say the name of the station you are calling and then yours, eg if calling from the shore to a rescue boat say “support boat 3 from race control”