I'm sure others can give more extensive answers, but, to start you off...

If you were a merchant, and living on the island, as opposed to a merchant on one of the ships trading at Deshima, you'd likely be the chief (opperhoofd). There was only a small number of people on the island. The chief, someone in charge of the warehouses, a doctor, and some dozen helpers. You would also be bored a lot. The Dutch were not allowed off the island, except to travel to the Shogun in Edo (Tokyo), this restriction was lifted slightly towards the end. Depending on the time of year you would have been preparing for the new trading season (the movement of ships was restricted by the monsoon, so they didn't arrive year round), or preparing for the yearly trip to Edo. You would not only be concerned with the VOC's trade, but also about your own. The chiefs at Deshima were allowed to trade on their own accounts, something the VOC didn't usually allow, which cold make you a very rich man. You would also have to keep the island's log (daghregister), of course. By order of the Shogun, you would only be allowed to serve for one year. (though some were apointed chief several times and so server for several years).

The only Japanese people allowed on the island were officials/translators who had to deal with the Dutch (only during the day), and prostitutes (who were allowed to spend the night). Since there were no wives or clergy on the island to make objections, the prostitute's visits were frequent.

Fortunately for us , some of the doctors and chiefs took an interest in Japan that went beyond trade, Isaac Titsingh is one example, after he returned he wrote about Japan. (google books, so parts are missing).