G'day Mat,
About the best bait for mulloway (dew fish) is live poddy mullet. You can get a bait trap suitable for catching poddys from any god tackle store. The staff will be able to tell you where to find poddy mullet.
Pin the hook just in front of the dorsal fin. Do NOT go to far down, if you touch the spine the poddy will die. You need the hook to go right through.
You will need fairly heavy tackle, minimum 20lb line. A lot of dew fishermen use hand lines with 100lb line. The 100lb line is not for the fish...is so it is thick enough not to cut into your hands.
You will find dew on beaches and in rivers. The golden rule is bream. Wherever you find bream, you will find dew. You can also use the same rig as you would for bream. So any of the common bream rigs will be fine.
itsaboat mate...Life is just a boat and then ya marry one !