First impressions count. This is well-known advice, but in an interview situation, a prospective employer is always going to be in a critical mode and may even be looking for an excuse to terminate the interview early, so first impressions are extra important. Anything you say will be assessed in the context of how you look—so look good!
Unless you are going for a creative role or one that clearly specifies a casual dress sense, you should dress conservatively. Err on the side of caution. If in doubt, copy examples seen in your local CBD. And remember to stay comfortable, eg. for men, if your shirt collar is too tight, then get bigger shirt.
Yes, men need to wear a suit—with a tie! And polished shoes. Even if the job doesn’t normally require this level of formal dress, it shows respect for the interviewer (and can distinguish you from other candidates). If possible, have someone else (eg. a woman) critically check your sense of style, including colour & pattern of tie, colour and texture of shirt, style and pattern of suit, suit material, etc. Some basics here include: not having a striped tie with a striped suit; shoes need to be darker than your suit colour; and don’t wear any flashy jewelry.
Women should wear smart, stylish business wear—not too masculine, but not too feminine. A skirt is recommended. Your suit should be a dark, conservative style. Do not wear anything close-fitting or sheer. Be careful to not wear too much jewelry, makeup, and minimum perfume (none is recommended). A natural , neutral style works best.
For both men and women, it’s a good idea to wear a conservative watch (or none), and conceal any tattoos, shell necklaces, suntan marks, etc. Also, fresh breath!
And make sure that you get to the address at least 10 minutes ahead of the appointed time. This will mean not only you’ll be on time, but you won’t looked rushed and disheveled (even sweaty) when you arrive at the interview.
The point is to be seen to be right for the role without initiating any distractions. You’ll have passed the first test and the interviewer will then start to listen to what you have to say.