The worst way to answer 'What are your weaknesses?' according to a 25-year hiring pro

Fg Trade | E+ | Getty Images

Acing a job interview is all about making a good first impression, and one big way to miss the mark is to answer an age-old question with a cliche.

Responding to the question "what are your weaknesses?" by painting yourself as a perfectionist or a workaholic will likely prompt an eyeroll from Tom Gimbel, CEO of the staffing agency LaSalle Network.

"Oh, yeah, that's a real weakness all right," says Gimbel, who says he's extended offers to "hundreds and hundreds" of people during his 25 years in the hiring business. "You want to be perfect and you work all the time. It's a trick answer."

Rather, when Gimbel poses that question to candidates, he's looking for two things: that you're self-aware, and that you have solutions for your shortcomings.

"The real question that employers have is not what your weaknesses are, it's what your solution to compensate for that is," he says.

Here's how to prepare a solid answer: Think about a technical or a soft skills you'd like to improve and how you're actually taking action on it.

For example, you might discuss that you're not as quick on a certain software related to your work, and you've realized you want to take some classes on it. Or, you might point out that you're not a great writer, so you're working with a writing coach or having a mentor proofread your emails.

"That's a weakness solution," Gimbel says. "We all have weaknesses, and we need to admit what we're not good at."

Overall, Gimbel's No. 1 underrated tip for excelling at a job interview comes down to a little humility: "Be honest about what you stink at."

Want to be smarter and more successful with your money, work & life? Sign up for our new newsletter!

Get CNBC's free Warren Buffett Guide to Investing, which distills the billionaire's No. 1 best piece of advice for regular investors, do's and don'ts, and three key investing principles into a clear and simple guidebook.

Check out: The top 15 jobs people most want to quit—No. 1 pays $144,000 a year

How this millennial making $80,000 in Italy and the U.S. spends her money
How this millennial making $80,000 in Italy and the U.S. spends her money