I can't offer too much insight since I was only in Sydney for 3 days back in 2010. The best advice I can offer you is bring double the amount of money you would usually spend if you were in an American/Canadian city (a 12oz regular drip coffee at Starbucks was 4.50 AUD, CocaCola at 7/11 was on special 4.00 for two cans, a BBQ duck at a shitty hole-in-wall chinese restaurant was close to 40.00 AUD)
A few places I went to:
Sydney Opera House and Sydney Harbour Bridge
Katoomba Scenic World
Three Sisters Rock Formation
Bondi Beach