You work hard. You cover your own responsibilities and go above and beyond the call of duty to make sure you're doing everything you can for your company. Your latest performance review reveals no startling weaknesses and illustrates you as an ideal employee. But still, for some reason, you didn't get a raise.

It's a harsh reality to face, especially when you're counting on that extra income. Not getting a raise can make you question the validity of your efforts, or even make you question your career decisions. But before you get too distressed about the situation, take a step back and work to understand why you didn't get a raise. There are several possibilities that could prevent you from getting a raise, and not all of them are a reflection of your performance:

1. You didn't ask for one. The first and most obvious reason you didn't get a raise is that you didn't ask for one. For many workers, asking for a raise feels uncomfortable; it could lead to rejection or make you fear that you'll be seen as greedy, regardless of whether or not you actually get a raise. Even though many companies care about their workers and reward them whenever possible, they also need to pay attention to their costs and remain as efficient as possible. If you don't explicitly ask for a raise, your supervisor might assume you're perfectly satisfied with your current salary and will keep you at that level instead of giving you an automatic increase.

How to improve: ask for one. It's as simple as that. Get rid of the negative stigma; asking for a raise won't make you seem greedy or entitled as long as you're prepared with concrete examples of your contribution of value to the company. If you don't ask for a raise, assume you won't get one.

2. You came in underprepared. It's also possible that you asked for a raise directly, but you weren't prepared with any information to support your request. When reviewing their employees, employers like to see logical arguments and tangible examples. If you simply say "I want a raise," but you don't perform any context or reasoning behind your request, you might not be taken seriously. The most successful candidates for raises support their request with average salaries and increases for similar professionals in the area as well as examples of their work over the past year.

How to improve: do your research. Come in prepared with as much information as possible. Don't make a presentation about it, but do become familiar with regional and industry statistics and use them to validate your request. The more fact-based you are, the better.

3. You perform your responsibilities well--but only your responsibilities. It's entirely possible that you have a flawless work review for your current responsibilities. That alone will not get you a raise. Workers that come in on time, execute all their responsibilities well, and leave on time are not viewed as "exceptional." They are viewed as "adequate." Adequate workers deserve to continue making what they currently make, while exceptional workers deserve something more. Exceptional workers go beyond their responsibilities--starting new initiatives, coming in early and staying late when necessary, and reaching out to others and helping the team whenever possible.

How to improve: make yourself exceptional. It won't do much to get you a raise right now, but if you consistently exceed expectations over the course of the next several months, you'll have ample material to demonstrate why you're an exceptional worker.

4. You took a personal approach. Raises are an objective matter, not a subjective one. If you ask for a raise but you make it into something personal, your employer may flat-out ignore your request. It could be that you need this raise to better support a spouse or a child, or that you're eyeing a new dream home in a better neighborhood. Revealing these personal situations may win you some sympathy in the short-term, but it will only decrease your chances of getting a raise. Employers don't want to hear about personal circumstances because salary raises are business decisions that should not be based on emotions.

How to improve: don't mention your personal circumstances. Frankly, it doesn't matter whether you "need" the money. What matters is that you deserve the money, and the only way to demonstrate that is through clear-cut examples and objective data.

5. You didn't show off your accomplishments. You've worked hard this whole year, but if you missed the opportunity to show off your greatest accomplishments, you shouldn't be surprised when a raise doesn't follow. Don't be afraid to brag during your review or during your formal request for a raise--this is the perfect opportunity to showcase what a valuable player you are. Use concrete examples whenever possible: instead of saying "I wrote a lot of good blog posts," say "I wrote 100 blog posts, which resulted in a 30 percent increase in web traffic." Instead of saying "I made a new workflow," say "I implemented a new workflow for 20 of our employees, resulting in higher employee satisfaction and a productivity increase of 10 percent."

How to improve: document everything and measure the results of your efforts whenever you can. Keep a running list of major accomplishments you achieve throughout the coming months, and use them as ammunition in your next raise request.

6. You didn't become more valuable. It could be that you simply did not become more valuable to the company. Consider a possible rate increase from your Internet provider: if the higher rate comes as a result of getting faster, more reliable service, you'll be far more accepting of it. The same goes for employers: why pay more for the same service? If you haven't made yourself objectively more valuable over the course of the past year, your raise is unlikely.

How to improve: increase your value as an employee by widening your skillset or increasing your efficiency. Take new classes, get certified in new areas, expand your range by learning from your coworkers, and increase your efficiency at your current responsibilities. Document your improvements and correlate them with your requested salary increase.

7. You aren't a positive team member. Being a part of a team means a lot more than just fulfilling your professional responsibilities. If you routinely complain or spread negativity around the office, even if you exceed your core responsibilities and objectively improve your skills, you'll be seen as a negative influence overall. Companies want to reward employees who do what they can to make the office a better environment, not a more negative one. If you catch yourself complaining, gossiping, or treating your coworkers impersonally, you'll immediately understand why you didn't get a raise at your last review.

How to improve: work to become a better team member. Turn negatives into positives by focusing on how to improve a situation. Congratulate other team members for their successes and support them when they fail. The more camaraderie you demonstrate on a daily basis, the more you'll be seen as a positive influence. This factor cannot be objectively measured. It can only be seen and implied.

Once you understand why you didn't get a raise, you can start planning for the future. If a lack or misallocation of effort is the main reason for the missing increase, find ways to improve your performance over the course of the next year. If the factors are mostly out of your control, such as the financial position of the company, decide whether you want to stick around or find a new environment to advance your career. No matter what you decide, understanding why you didn't get a raise can help you better prepare for the next phase of your career.