Management consultant, Peter B. Stark, says that before asking for a raise, workers need to decide how they intend to demonstrate their worthiness. Stark suggests employees keep track of their accomplishments and compare their wages to industry standards. He also suggests that workers ask for a higher increase than they are actually seeking in order to leave room for negotiating.
See "Ways to bargain your way to a better salary", T. Shawn Taylor, Chicago Tribune, October 28, 2003