You need to take a look at the Grid Wind forcasts for changes in wind speed with height first, The U.S.A.'s National Weather Service duidlines give 6 knots per 1,000 feet vertically and 40 knots per 150 nm horizontally as values of wind change indicitave of shear critical for Clear Air Turbulence (CAT).
These values are easily exceeded by the Jet Streams aorund the mid and southern latitudes in Australia. CAT around jetsteams is particularly bad where the jet is concave to the pole (i.e. in Australia on the southern edge of the jet, when it is turning to the south.) These are the places you will see the Met department predicting turbulence on the SIGMET chart. Undertanding where it is will allow you to make a diversion decision (i.e. North or South) to find smoother air, depending where you are in relation to the area.
Look also for subsidence inversions - typically indicated by that dirty brown line in the sky, sometimes you will see turbulence induced Altocumulous at this level as well. The air is smoother above the inversion, and quite bumpy around the inversion, due to the change in wind at that level.
Watch out for mountain waves on the Tassie ranges or the southern end of the Great Dividing Range when the conditions are right (wind close to 90° to the range, and increasing with height, stable day).
Most other turbulent areas are indicated by the presence of weather (i.e. fronts and the like.)