Go through your results for flights to Xiamen in China with Netflights. Although Air China usually has the best prices, it's best to double check what's available for your travel dates.
If these flights are too expensive, try searching for a different time of year. It's likely that prices for both flights and accommodation in Xiamen will be higher during July. Meanwhile, October is nearly always the cheapest time to fly. So if your dates are flexible, consider looking at different times of year.
Look out for flights with Air China, as they often have good deals. Or broaden your search by looking at other airports in China.
You can also broaden your search by looking at more than one departure airport. Have a look around – you might be able to save by flying from a different airport or city.