Sydney has an enormous number of places to drink and party. A limited number of venues have 24 hour licenses, however the majority close before 3AM and some as early as 11PM, particularly if there are nearby residents. Most venues will have door staff checking photo identification to determine that you are over 18. Admission is also commonly refused to those who seem visibly drunk. More popular venues have discriminatory door practices, the most common of which is refusing entry to groups of men who are not accompanied by women.

Most places have at least a basic dress code. For most generic pubs, men should wear closed toe shoes (not running sneakers), full-length pants, and a shirt with sleeves (not a singlet). For clubs, men should don neat business-style shoes.In almost all cases, women can dress more freely, but a small number of places require closed shoes or dressy sandals or high heels.

Be aware that something called a 'hotel' may not actually be a hotel. Many pubs around Sydney are called hotels, but only very few can ever offer you a place to sleep. Hotel pubs are usually found on a street corner with at least one ground-floor bar, and are usually a few floors high (though not all floors may be open to the public).

Entry charges for live music or DJs are usual and range from $5 to $30 depending on clientèle. Entry charges are rare if you're going into a pub for a drink.

There is a taxi shift change at 3AM, and it is notoriously difficult to catch a taxi anywhere between 2:30AM and 3:30AM. Also beware that there is currently a government enforced lockout at many establishments between 2 and 5AM - which means that you need to stay inside or you won't be able to get back in - even if you go out for a cigarette (smoking is illegal inside). Ask the bouncers or some locals if you're unsure and they will tell you which places are affected by the lockout and which aren't.

Some types of nightlife are concentrated in particular areas:

Backpackers drink near the hostels, and will find a lot of fellow budget travellers in pubs in the Eastern Suburbs Beaches like Bondi Beach and Kings Cross in the City East
In some ways Irish pubs are a global phenomenon, but they've certainly taken Sydney by storm. Irish pubs are concentrated in both The Rocks area and the southern area of the city. They are outrageously popular on the 17th March for St Patrick's Day.
Business pubs also cater to the city crowd: lawyers, financiers and brokers and are very busy Friday nights when the city workers are let loose for the week.
Large nightclubs are concentrated in the Darling Harbour area.
Sydney's large gay scene is concentrated on Oxford Street in City East although it still has a large range of pubs and clubs for all ranges of sexuality and is a prominent nightspot for many party-goers.
Sydney's students drink in the Inner West.
Some nightclubs and Sydney's younger party-goers are found in North Sydney.
There are many great nightclubs in Sydney, unfortunately they are very spread out so it would be a good idea to get an idea of were you want to go. Check guides in Friday's newspapers, or the free guides available in music stores and youth clothing stores.