The first time Deborah Van de Grift asked her boss for a raise, she walked in unprepared, and left empty-handed.

Several years later, when a vice president at the health care organization where she worked went on an extended leave, she was called upon to pick up some of the slack. Twelve-hour days and six-day weeks at the office followed as she performed not only her own duties as human resources manager but her boss’ work as well.

Again, Van de Grift felt she deserved more money, and this time she prepared meticulously. For a year she kept a list of all the extra work she did, and all the ways in which she had excelled. She then used that list as the basis for a detailed memo outlining her contributions to the company and asked for a meeting with the chief executive.

At first, he was reluctant. But Van de Grift was adamant, asking him to take a hard look at the memo she had written. Eventually, he relented.

"I got the raise," said Van de Grift, 47, who now works as a career coach in Freehold, N.J. "But I really had to be forceful about it. That was the key — really showing that I deserved it."

Most people probably think they deserve a raise. But there’s a difference between deserving a raise and actually getting one. To bridge that gap, career experts recommend a variety of strategies that can help convince the boss that you’re worth more than you’re getting now. All of their tips, however, boil down to two basic principles: Be confident, and be prepared.

Barbara Herzog, a career consultant in Washington, said the path to a raise begins as soon as you take the job. Ask for regular performance reviews from the outset, even if they’re informal, she said. That way, you’ll know if you’re veering off track from your employer’s expectations. And if you’re meeting or exceeding expectations, then performance reviews give your boss the chance to say so. That kind of praise could come in handy when you’re ready to cash in your chips and ask for more money.

Herzog said she also counsels people to do what Van de Grift did: Keep track of accomplishments. And every once in a while, do things to make sure the boss knows about them. "Ask people who have complimented you on your work to send a quick letter or e-mail to your boss," Herzog said. "And do that not just at performance review time, but any old time."

When it comes to actually making the pitch for a raise, attitude is important. Bruce Schneider, founder and chief executive of the New Jersey-based Institute for Professional Empowerment Coaching, said he’s most receptive to the idea of giving a raise when his employees are upbeat and confident, but not pushy.

He also appreciates a sense of humor. "Find a day when your boss is in a good mood. And then you might ask, ‘On a scale of one to 10, how willing would you be to consider having a conversation about giving me a raise?’ " Schneider said. "That at least opens up the possibility. Once the door is open, then the conversation can proceed."

Herzog said that threatening to leave your job unless you get the raise almost never works. "Ask for your raise in a very positive way," she said. "Avoid veiled or outright threats."

Another common mistake is to base your request on what your co-workers are making. "The biggest ‘doesn’t work’ is ‘I found out what my colleague makes and I demand the same,’ " said Deborah Keary, information center director at the Society for Human Resource Management. "That’s the worst thing you can possibly do."

At the same time, it’s a good idea to do a little research beforehand, and figure out what people in your position at other companies make. You should also have a handle on your company’s financial position, to make sure your request is in the ballpark.

"To you, 10 percent might sound reasonable, but to them it sounds astronomical," Keary said. "To ask for 10 percent, that’s uninformed, unless you really changed the world or made the company $87 billion."

Asking for a bump in pay of 3 to 4 percent, she said, is more likely to be well received.