This is a very old thread.
But for anyone interested.
You need to be able to read weather and work out what will be out and about.
During the day you really want to look for humidity, little cloud cover, little to no wind and of course warm temperatures. This will bring out certain species of snakes, agamids and monitors.
(No clouds = better for basking, high temps = reptiles are endothermic, no wind = helps with surface temperature and more insects will be around, humidity = brings out array of food for reptiles to hunt)
Now if you are still keen to find animals in the cooler months during the day you can still find a few things.
But you have to find a great spot with very little traffic and lots of rocks and logs to flip.
As to what rocks and logs to flip, you work that out for yourself.
(Reptiles will hide under debris because it's a easy way to stay warm and safe during the colder months. Flipping won't be very successful during summer as the debrii will be too hot, generally)
Now night herping can be very easy and usually produces a lot of animals
Go to a national park, look at a good field guide and work out what's there. AROD is a good website for that as well.
Depending on what you're looking for you can simply drive the roads at low speeds looking for animals soaking the road heat up or you can get out and walk.
Both will produce differet things.
Driving will give you animals that live in habitats that aren't exactly specific. (I.E easier to find a Mulga driving the roads than it is to find a leaf tail on the roads, but that's not to say you won't)
Night walks, bring a good head torch and at least two more torches (they break), look for eye shine. You will soon be able to work the difference between insects and reptile eye shine.
Night walks allow you to really target what you're looking for. (I.E levis in sand dunes)
Favourable conditions for night time herping include high humidity (brings out insects which brings out frogs and lizards which brings out snakes), moon phase (new moon is generally best, less light for reptiles to be seen by predators), high temperatures (endothermic), low pressure system (humidity and cloud cover) and cloud cover (can help on nights when the moon isn't so empty, also acts as a insulator and keeps the air warmer for longer).
Herping is just like any other skill, some people have a natural nack for seeing minute geckos on the road while doing 130km/h or finding stuff by pure coincidence and luck.
Most people will have to work at it for a while to get results.
It really helps when you have someone to help you out and point out certain things to you that you might otherwise miss.
Just note these are general hints. Not all animals love these conditions.
Cheers
Mulgaaustralis