Practice paper after Practice paper after Practice paper....
I especially try to find all the long answer questions (5+ marks) i can and perfect the answers. common ones are the AC vs DC, Westinghouse Edison, Einstein Plank, the missner effect and magnetic levitation, Photocells, BBR and the photoelectric effect and michelson/morley.
Also revise pracs and know the HSC verb list.
but most importantly
RELAX - its all gooooood XD.