i went to Sydney for about 7 days on last December.

here are some tips from me:

1. get the public travel pass. you can use almost all public transport with a single pass for a week. i travelled to katoomba by train, visiting the blue mountain on one day and the newcastle (if not mistaken) on the other day.
2. always check the bus timetable using your smartphone. the buses are very accurate with 1 minute tolerance. dont forget to check for the last service should you wish to stay out late.
3. get a good sim card for your smartphone. i used Optus which costed me AUD10 for 5 days, with 500mb of high speed quota daily.
4. you may enjoy any cuisine along the streets, they look delicious. but for muslims, you may try the chinatown or for quick access the Nando's chain. there are also few shops selling sandwiches at Circular Quay, but what i enjoyed most was a Lebanese restaurant at Granville (you have to take a train about 30 mins from Circular Quay) called El Jannah, and priced reasonably cheap.
5. always check for exchange rate at money changer if you need extra cash. they might even impose a certain amout of commision.
6. be friendly and dont feel shy to ask from the locals.
7. lost item? check back the last place you had the item and ask the authorities. i lost my iphone 5 and they still have it waiting for the rightful owner to claim.

brought one adapter and one 4-multiplug extension. works great for me