As of 2015, women working full time earned 80 percent of what men working full time did, according to the U.S. Census Bureau. So how can you make up that ground? Use these tips to try to eliminate the wage gap:

Recognize that negotiating is an asset

Many hiring managers are prepared to give you $10,000 to $15,000 more than they offer — but you have to ask, said Kate Gremillion, CEO of Mavenly + Co., a professional development firm. Negotiating can even help you as you are getting started in a career. More than three-quarters of employers said recent graduates appeared more confident when they asked for more money, a NerdWallet survey found.

Research using industry contacts

You probably know you should research your market value before negotiations. But don't just use online resources like Glassdoor and PayScale, Gremillion said.

You will get more reliable information from industry contacts, ideally a mix of men and women. You don't have to ask what your contacts earn, just a reasonable base salary given your level of experience.

Don't rush to say a number

Many experts suggest talking numbers only after the hiring manager offers you a salary. That way, you don't ask for less than he or she was prepared to offer. But if you are asked for your desired salary on a job application or during the interview process, hopefully your contacts have given you a good idea of the base salary you could expect. Consider adding 10 to 15 percent to that number.

Tie your contributions to business strategy

Make the case for a higher salary by explaining how your contributions will increase the company's profits and how you have helped previous employers. If your role doesn't directly affect the bottom line, show your worth using another meaningful metric. One of Gremillion's clients, a nurse, negotiated more money by pointing out the high patient satisfaction scores that she received.

Ask for nonsalary benefits

Perks other than pay can include flexible work hours or professional development funding. Explain how these benefits will ultimately benefit the company. An example: "I do my best work when I feel valued. Feeling valued would mean being given the trust to work from 7 a.m. to 3 p.m., when I am most productive. How can we create a situation that looks like this?"