According to professional social network LinkedIn, mentors play a key role in helping women "shatter the glass ceiling." In a new study, however, LinkedIn found that nearly 20% of respondents never had a mentor.

"Tooting your own horn is just one of the many ways you can increase the likelihood that you'll shatter the glass ceiling and snag keys to that corner office," says LinkedIn's Connection Director, Nicole Williams. "If you're uncomfortable speaking up about your accomplishments, then often times, your best bet is to seek out a sponsor or a mentor in your office who can vouch for you."

In the study, which surveyed 1,000 US women, LinkedIn asked those who didn't have a mentor why they never had one. Fifty-two percent of the women responded that they had "never encountered someone appropriate." LinkedIn also asked the women who had never been a mentor why they weren't mentoring another professional, and 67% responded that no one had ever asked.

"Waiting in the wings for a mentor to discover you or hoping that your company will implement a mentoring programme aren't your only options," Williams says. You can search for professionals by title and find mentors in your zip code by using LinkedIn's Advanced Search option, she says.

While some women have not been proactive in seeking a mentor or mentee, LinkedIn did find that there are more women taking the time to mentor others. Of Gen Y women, 51% said they are being or have been mentored by women, compared to 43% of Gen X women. Boomer females ranked lowest, with 34% saying they are or have been mentored by women.

Additionally, LinkedIn investigated what women depend on their professional network for. The top responses included professional guidance, recommendations, career advancement, collaboration and keeping current with industry news and trends. Job hunting came in last place on the list at number six.

For people seeking a mentor, Williams offers these four tips to set you on the right path.

1. What are you looking for?

Be sure you know what you're looking for in a mentor, whether it's having the insight of an expert to help answer questions or finding someone you want to emulate. Williams says to start with a goal in mind because the better you're able to define what you're looking for, the more apt you are to find it.

2. Think outside the box

Mentorships don't have to be formal, Williams says. In thinking that way, people tend to miss out on potential mentors such as neighbours, relatives or colleagues that may be right under their noses.

3. Just ask

Williams says that unless someone is actively seeking a mentee, you have to be proactive and set the grounds for the relationship. "Don't make it sound like a death sentence," she says. "Mentorship is responsible work but if there isn't a promise of fun, initiative or excitement on your part, don't expect your would-be mentor to embrace the opportunity to help you."

4. Reciprocate the relationship

You can't forget that mentorship is a two-way street, Williams says. Don't expect them to do the heavy lifting for you - be sure to make it easy on them, for example offering to meet closer to their office-and make sure you show that you're grateful for their time and guidance.