How to complain effectively when traveling Informative - Complaining effectively.
A few of my favorite tips:
Take immediate action, complain to the right person, keep it polite, and ask for what you think is fair.
Best piece of advice: Keep track of anything and everything you’d want to know if it were your job to resolve the situation retroactively.
More information here:
(Edited to fix link to page 1 of article.)