I help out on pages relating to the Māori people of New Zealand, and also Polynesia and the Pacific generally. Being able to speak a Polynesian language is a big asset in this area.
One of my first major projects was the recategorisation of en:Category:Polynesian mythology to reflect the distinctiveness of Polynesian cultures. I was also the instigator of the infamous great Polynesian article deletion debacle of March 2006, where I ended up teaming with Canadian en:User:Bucketsofg to find sources and save articles that I proposed for deletion. You had to be there.
I like to edit the articles to weed out misconceptions and wrong assumptions, and to revert vandalism.
I am interested in trees and plants, especially those of the northern North Island, and the subtropical and tropical islands to the north. I have started articles on trees like en:Pouteria costata and the endangered climber en:Tecomanthe speciosa. I am also interested in palm trees, especially the subtribes Archontophoenicinae and Rhopalostylidinae which are endemic to my area of interest.
I also do some editing on articles relating to the birds and other fauna of New Zealand.
Flowing on from my interests in botany and Polynesia, and from my involvement with the Māori Wikipedia, one of the biggest contributions I make to Wikipedia, as far as using up my own time goes, is to create and source images to illustrate the articles. To this end, I have upgraded my camera gear and tried to improve my skills. And I have learned how hard it is to take a decent photo, even of a static thing like a tree.