The radiant of the Geminid meteor shower above the northern horizon as seen from Adelaide at 3:00 pm ACDST on December 15, similar views will be seen from other sites at equivalent local times.
The Geminid Meteor shower is at its peak from the point of view of Australian's on the mornings of Tuesday 14 December and Wednesday 15 December. The actual peak is December 14, 11 UT, which is 10 pm AEDST (well before the radiant rises), but unlike the Leonids the Geminid peak is broad, and we should see decent rates on the mornings of the 14th and 15th (better on the 15th).
The best time to observe is between 1 and 4 am (daylight saving time, 12-3 am non-daylight saving time), with the highest rates between 2-3 am daylight saving time.
The Moon will have set by the time the Geminid radiant is high enough in the northern sky for decent meteor rates to be seen. In Australia we should see roughly a meteor every 3 minutes (depending on how dark you sky is, the more light pollution, the fewer meteors you see).
When looking, be sure to let your eyes adjust for at least 5 minutes so your eyes can be properly adapted to the dark. Don't look directly at the radiant site, because the meteors will often start their "burn" some distance from it, but around a handspan up or to the side. Be patient, although you should see an average of a meteor every three minutes, a whole stretch of time can go by without a meteor, then a whole bunch turn up one after the other.
Make yourself comfortable, choose an observing site that has little to obstruct the northern horizon, have a comfortable chair to sit in (a banana lounger is best), or blankets and pillows. A hot Thermos 0f something to drink and plenty of mosquito protection will complete your observing preparations. As well as meteors, keep an eye out for satellites (see Heavens Above for predictions from your site). The sky will also be particularly beautiful, with the constellations of Orion and Taurus gracing the north-western sky and Saturn and Venus rising in the east.
You can check meteor rate predictions for you local site with the NASA meteor flux estimator (scroll down to 4 Geminids in the SHOWER box, make sure you have your location and date correct as well). You can follow world wide Geminid counts at the IMO live Geminid site.
UPDATE: Comet Al writes in the comments: Have look at this if you have clouds, Radio Meteors, sound added. rgds Cometal
Go and have a read, it's great!
Cloud cover predictions can be found at SkippySky.