By Denene Brox, for Yahoo! HotJobs

There are many factors that contribute to your career success, but one that's often overlooked is the art of being an assertive employee. If your idea of standing out as a good employee is to simply show up every day and do the work put in front of you, you are losing out on many opportunities to advance your career and earnings potential.

"Assertiveness is the balance between being mousy and being aggressive," says career coach Cheryl Palmer. "It is standing up for yourself, but not at the expense of others."

For some, striking that balance may mean not being so harsh and bold. For others, it means stepping up and asking for what you want. Palmer says that taking an honest, introspective look at yourself is the first step to measuring your level of assertive self-expression.

So in what areas of your career is it crucial to become assertive? Following are three key areas where assertiveness pays.

Salary

"Being assertive can earn you more money throughout your career," says Palmer. "I have seen many clients lose thousands of dollars because they are not assertive enough to negotiate salary or speak up and ask for a raise. Women in particular tend to have issues with assertiveness when it comes to money."

Career coaches agree that if you're waiting for your boss to notice your contributions and reward you with higher pay, you're losing out. Dee C. Marshall, a career and life coach, says to put your request for a raise in writing, outlining all of your achievements and ask for a meeting with your boss to discuss. "You must go confidently and ask," Marhsall says. "No one is going to hand you anything."

Meetings

"Meetings are the perfect situation to be assertive," says career coach Rebecca Kiki Weingarten. "It can be an opportunity for you to shine and show your stuff."

Using meetings to share your creative ideas and solutions to problems will help you stand out in front of key leaders. Weingarten points out that even asking the right questions in a meeting is being assertive.

"One of my clients was promoted to vice president of the company just because he contributed in meetings," says Palmer. "He had been at a much lower level in the organization, but his contributions were so salient that upper management saw his potential and promoted him. He ended up making six figures."

Setting Boundaries

If your coworkers are driving you crazy or bullying you around, it's time to put good boundaries in place. Palmer says that there are a lot of workplace bullies, and being assertive allows you to set limits without being becoming a bully yourself.

Learning to say "no" to projects when your own workload is full is an important skill for employees at all levels. Saying "no" is the hardest mode of assertiveness for some people, says Palmer.

"Assertiveness training can be beneficial not only for people's careers, but in their personal lives as well," she concludes. "People who want to feel good about themselves and their work need to be assertive."