There's more to getting promoted than showing up and working hard.

It's about going the extra mile and contributing in ways that aren't expected, said Ian Siegel, CEO of ZipRecruiter.

"Do your job as well as you possibly can, and once every three months surprise us with something extra," he said. "It's when you exceed our expectations that you will have the opportunity to get a bigger role."

But if you think you're doing that and you still aren't reaping the rewards , the reason you aren't moving up could be a little more subtle.

You haven't asked

Managers are often in charge of a lot of people. So you might need to be the one to put your career growth on your boss' radar. Don't shy away from flat out asking for a promotion.

"Make it an actual topic of conversation," said Joel Garfinkle, executive coach and author of "Getting Ahead: Three Steps to Take Your Career to the Next Level."

"You need to share your aspirations openly and specifically with your boss and ask exactly what you need to do to get promoted."

You aren't showing leadership skills

Doing your job well shows you are doer, but not necessarily a leader.

"Working hard and working your butt off doesn't mean you will ever get promoted... you have to demonstrate that you are going to be better for the company at the higher level," said Kathy Caprino, career and executive coach.

You need to share your aspirations openly and specifically with your boss and ask exactly what you need to do to get promoted." Joel Garfinkle, executive coach

And that means finding ways to showcase your leadership capabilities . For instance, pitch a new assignment to lead, raise your hand to manage a new project, or volunteer to teach a session at work in an area of your expertise.

"Get yourself in front of people so you are demonstrating capabilities that your job doesn't allow you to show," said Caprino.

You're too humble

Your boss might not know all the reasons you've earned a promotion.

Nobody likes a braggart, but you need to be able to showcase your hard work and accomplishments.

Lack of visibility can be a hurdle to a promotion, said Garfinkle.

"Don't assume that your hard work will be noticed," he said. Learn how to brag effectively. "Have the mindset that you are sharing facts." He suggested providing regular progress reports to your boss on projects.

"It's the mindset of giving information to your boss to help him or her communicate on projects and success and that you just happened to be the centerpiece of those stories."

You don't have good relationships

It's imperative that the people above and below you respect you.

"If your boss doesn't like you, you aren't getting a promotion," said Caprino.

Being a team player is also crucial.

"Working well with others is incredibly important for people to see you as a valued partner," said Blair Decembrele, a career expert for LinkedIn.

Asking for feedback from peers after a project or assignment can help open the lines of communication and keep relationships strong, she added.

Establishing mentors and sponsors throughout the company can also help you move up the career ladder.

"You need a mentor or sponsor or someone in the company you trust and respect that you can learn from," said Caprino. "Someone who is powerful and will open doors for you when you aren't in the room."

You don't check the boxes for the next level

Being good at what you do doesn't mean you are ready to move on to the next level.

Don't just look at the job description of your current job. Review the responsibilities of the role above you and look for any gaps or areas where you can improve.

"Look at the next level and what that position requires and then look at your current skill set and the ability to do that position and work toward closing that gap," recommended Garfinkle.