Last month Marc Cenedella, founder and CEO of Ladders, the leading career platform for jobs paying $100,000 and more, was advising a female executive with 20 years' experience in marketing. She wasn't happy with the salary offered by a prospective employer, but she was sheepish about negotiating.

Cenedella advised her to tell the employer that she was hoping to earn $15,000 more because of a move from the Southwest to New York City, which had a higher cost of living and higher commuting costs. She did so, and within three days the company agreed to the increase.

Cenedella said many workers feel compelled to take the first offer, concerned they'll be perceived as rude or ungrateful if they negotiate. "The biggest mistake people make is that any negotiation is too much negotiation for them," he said.

Negotiations like this are taking place more often these days. A record low unemployment rate of 3.7 percent is boosting the confidence of workers and causing more people to leave jobs to pursue jobs with six-figure salaries, said Andrew J. Sherman, a partner at Seyfarth Shaw, who helps small and midsize enterprises negotiate six-figure salary contracts with prospective employees. "People are seeing there are more opportunities available to them," he said.

Cenedella said the days of working in one job most of your career are long gone. Companies "don't have a loyalty to you, so you don't need to have loyalty to a company." That means there's more job-hopping and opportunities for new negotiations to get you to a higher salary.

Getting to a six-figure salary "is something job seekers should aim for if they're not there yet," said Vicki Salemi, a career expert for Monster, a worldwide job site. Sherman said it's an important socioeconomic benchmark "that helps people define themselves quantitatively."

It's not just traditional white-collar jobs that can earn you six figures. A new analysis that Monster conducted using the Gartner TalentNeuron tool of the top 10 job listings offering six-figure salaries in the past year found heavy- and tractor-trailer truck drivers among software developers, sales managers and computer systems engineers. LinkedIn's 2017 Salary Report found that even those early in their careers can make six figures, citing investment banking analysts and associate brand managers as having a median income of more than $100,000.

So how do you successfully get to six figures? Leading experts weigh in with their top tips.

1. Know your worth. Consult professional organizations, mentors in your industry and colleagues to find out the salary range for someone at your level so you have a solid foundation going into salary negotiations, Salemi said. She suggests practicing the conversation, role-playing with a friend, if you haven't engaged in this type of negotiation for a while.

At the same time, Sherman cautioned against overvaluing yourself. "Even though it's a competitive marketplace, some people have an inflated perception of their worth," he said.

2. Don't accept the first offer. Employers almost always have an additional $5,000 or $10,000 available, yet most job seekers, concerned about appearing ungrateful, just accept the first salary that's put on the table, Cenedella said. Consider that as a starting point.

He suggests asking for more by using positive language and separating the negotiation from the role with phrasing like, "This would be a meaningful, wonderful step forward in my career. I'm thrilled about the position, and the only thing separating me from it is the matter of pay. I hope we can get that out of the way."

He said you can engage in a few rounds of negotiating; don't stop until the employer says, "This is our final offer." Even if you're happy with the first offer, don't accept it, Salemi said. "It could be even higher, making you even happier." She says there's no harm in asking if there's any possibility to increase the offer. If an employer can't come through on salary, ask if there are other compensation opportunities, like a signing bonus.

3. Give a reason for asking for more. Perhaps the job requires more travel, taking up more of your time and resulting in more childcare expenses, or is in a new location with a higher cost of living. Cenedella says providing a rationale for the increase "always helps these negotiations."

4. Clearly communicate your expectations. Let the employer know the critical factors that would encourage you to consider a role outside the one you're in. That helps the company tailor an offer to you, said Amy Schultz, director of product recruiting at LinkedIn. Dr. Steven Lindner, an industrial organizational psychologist with The WorkPlace Group in Florham Park, New Jersey, who has handled many six-figure job offers over the past 20 years, said it's important for candidates to think through what they really need to feel good about doing the job.