Hiring is a tough nut to crack. The amount of dilly-dalliers that hide behind good looks and quick wit is impressive.

So how do you weed out bad candidates?

It’s not easy to uncover who’ll be the right sales hire for your company, and the criteria that makes someone good or bad will differ for everyone. But I want to share what’s worked well—consistently and historically—for us here at Close.io.

Here’s 20 red flags to look out for in your sales hiring process.