If you want to know what your customers are searching for on Google, give the Google Keyword Tool a whirl.
Firstly go to:
adwords.google.com/select/KeywordToolExternal
...and change the geographical targeting to New Zealand (assuming you are targeting New Zealand) by clicking the Edit link after the text: "Results are tailored to English, United States" which is the default.
Then make sure the radio button "Descriptive words or phrases" is selected, before entering possible keyword phrases into the box headed: "Enter one keyword or phrase per line:" and clicking the "Get keyword ideas" button. (You will probably also have to enter one of those annoying codes, known as a captcha, to prove you are a human, rather than a computer).
For example if you make aluminium doors, then you could enter "aluminium doors" and click the button. Google will then return a number of other suggestions that real people have keyed into Google. The numbers beside each variation, while not being 100% accurate provide an indication of the relative demand of each term.