For all question you may have about customs in Hong Kong, you may want to check the official website:
www.customs.gov.hk/

The duty-free concessions granted to a passenger are as follows:

• 1 litre of alcoholic liquor with an alcoholic strength above 30% by volume measured at a temperature of 20°C
• 60 cigarettes or 15 cigars or 75 grams of other manufactured tobacco.

Prohibited/controlled items:

• Importation/exportation of dangerous drugs
• psychotropic substances
• controlled chemicals
• antibiotics
• arms and ammunition
• fireworks
• strategic commodities
• rough diamonds

Textiles, animals, plants, endangered species, telecommunication equipment, game, meat and poultry into or out of Hong Kong is governed by laws. Any import/export of these items must be accompanied by a valid licence or permit issued in advance by the relevant authorities, unless otherwise exempted by laws.

Again, be aware that if you go to mainland China rules might be slightly different so do check beforehand.

Note: There is no restriction on the amount of currency you can bring in.

Driving Licence

If you want to drive in Hong Kong, all you need if a valid from your own town country. If your country is a recognised and approved one, then it is all you need.

Check here to find out if you are from an 'approved' country from the Transport Department. Otherwise there is still the option to get your own Hong Kong driving licence. You will have to pass a driving test with three parts which are a written exam, an exam on driving techniques and a practical road test.