[Aussie Mike]

The main thing is to have the fill point for the system as high as possible. Air bubbles will make their way up to it eventually as the water pump pushes coolant through. The old trick used to be to leave the radiator cap off while the engine runs for a while and keep an eye on the level to see if it drops. You might have to wait a while till the thermostat opens but the dropping coolant level indicates the air is being purged out of the system.

Cheers