Example:
Rottnest Island traffic, Helicopter Romeo Tango Quebec, Robinson R44, currently one zero miles east of Rottnest, one thousand five hundred in-bound to join right downwind runway zero nine. Estimate circuit time three zero (meaning actual time to join the circuit e.g. 1330hrs) Traffic Rottnest.
From there I make a 5 mile call then 3 mile call before making my downwind call, base call then final.
Even if no-one is there, is excellent airmanship and keep in the back of your mind that someone is always listening!