As the co-owners and founders of boutique staffing agency The Grapevine, Lori Zuker Briller and Rachel Zaslansky Sheer interview "thousands" of candidates each year.
Their goal is to match strong candidates with "cool, unique and interesting" roles as varied as executive assistant, estate manager and personal chef, Briller tells CNBC Make It.
Drawing on 20 years of running The Grapevine, Sheer and Briller shared their top hiring insights in their upcoming book "Straight From the Grapevine: How to Crush Your Job Search."
According to Briller, a candidate's online presence is one of the most "impactful" considerations in the job process.
Candidates should take a hard look at their profiles and ask themselves, "Who are you online? What is your narrative and story online?" she says.
If a candidate's social media posts or online content don't align with the image they present in interviews, that can be a "definite red flag" for hirers, according to Sheer.
For example, if someone applying for a child-care role posts content that's "not on-brand" for a nanny, "it could cost them the job," she says.
In Briller's view, it's best to avoid posting, liking or sharing any content that could call your professionalism into question, particularly on career-focused platforms like LinkedIn.
Recently, Briller says she's seen an uptick in candidates sharing controversial or overly negative opinions on LinkedIn.
"There's a lot of ranting going on," Briller says, particularly about people's frustrations with past jobs or the hiring process.
Even if your view is justified, venting about a negative job experience online could make you seem like a "disgruntled employee," career coach Eliana Goldstein previously told CNBC Make It.
According to Goldstein, expressing resentment or anger in a social media post could cause hirers to question your attitude and professionalism.
It's best to discuss those feelings "with people you're really close to and trust," rather sharing them on the internet, she says.
Similarly, Briller advises the job seekers she works with to talk about their career challenges with friends and colleagues, instead of "putting every thought out there" online.
She tells candidates, "Look, it's not my place to have an opinion. If this is what you want, great. But just be careful, because hiring parties, HR people might see that as problematic."
Some candidates are "really resistant" to this advice, Briller says: "They're kind of like, well, it shouldn't be any of their business."
Still, job seekers need to accept that their online presence is fair game in the hiring process, Sheer says.
"Everyone checks, everyone Googles, everyone looks on social media now. It's just part of it," she says.