Once you've done some careful planning about the raise you want and why, you're ready to focus on the actual meeting with your boss.
Start by scheduling a meeting time when your boss' stress level and workload are manageable. An informal setting like lunch often works because it allows you and your manager to relate on a more personal level. Make sure to articulate in advance, however, what the meeting is about, so your boss can prepare. Also bring notes or materials that support your accomplishments, in case your boss wants to discuss them during the meeting.
The next five steps will help you with the actual discussion of your raise.
1. Set a goal and practice.
Before you meet face to face, decide on a number that you'd be satisfied with and prepare how you'll respond if you don't get it. You also may want to practice your tone on a family member or friend prior to the meeting, because there is a fine line separating the assertive/sincere and boastful/arrogant approaches.
Now, on to the actual discussion. If you're underpaid and you know it, don't complain. Instead, remain calm, positive and professional. Tell your boss about what you enjoy working at the company. Talk about your performance in a factual manner and provide concrete examples of how you add value to the organization. When it comes time to pop the question, use the word "compensation" rather than "raise" or "money." In the event that your boss declines your raise, don't close your ears to the rest of the discussion. She may be willing to offer you other perks instead, like extra vacation time, flexible hours, or a nice dinner with your significant other on the company.
3. Negotiate.
Despite your best efforts, you may not get the compensation you've earned. Sometimes the only way to get a serious pay increase is to switch to a new position. Or, you could ask your boss what you need to do to receive an increase, and if it's possible to revisit the issue in a few months. Do not give an ultimatum, unless you are prepared to walk out the door. Even if you have another job offer in hand that pays more, you cannot assume that your manager will make a counteroffer.
4. Escalate the matter.
Your boss may tell you that she would like to give you a raise, but her hands are tied. If this is the case, ask her if the two of you can schedule a meeting with the higher-up responsible for the decision. Do not go over her head without her knowledge, and make sure she is kept on the loop on all matters concerning your compensation.
5. Follow up.