I remember interviewing someone for a position at Square years ago when I was an engineering manager there. This candidate had every soft skill needed to excel in the role, but they weren't familiar with our technology group.

Not knowing the technology used at a big tech company seems like a good enough reason not to hire someone – but 80% of the technology we use now wasn't around then either. In hindsight, the biggest mistake I could have made would have been not hiring them, and it was sheer luck that made me realize that at the time.

Below, I'll explain a few more main ones hiring mistakes — including some I've narrowly avoided and others I've personally done. Use this information to guide your hiring decisions so you have confidence in the people you choose for your team.

Related: Why let people fail now so they can succeed later

1. Don't hire talent over character

“How familiar are you with Javascript?” is one of the least valuable questions you can ask in an interview. Don't get me wrong; there is a place for technical review at length employment process. But as a direction, there are better uses of your time.

At the end of the day, I can teach Javascript to almost anyone – or at least anyone who is likely to get far enough in the hiring process for me to have a face-to-face conversation with them.

I can't necessarily teach a candidate how to get along with me. COMPLIANCE it can be nurtured to a certain extent, but most of it is innate. It's either there or it's not.

Your time in an interview is much better spent asking questions that speak to your candidate's character. I have written a completely separate article about this, which you can read below.

Related: I've interviewed thousands of candidates – here are the 2 questions I asked them all

2. Don't assume that origin is the same as value

The fact that a candidate went to a prestigious school or worked at a big company can get them in the door. But it should never be enough to give them the job completely.

Not everyone who went to Harvard or Yale is a genius, and not everyone who worked at Microsoft is a visionary. An institution's reputation may suggest something obvious to the people associated with it, but it does not guarantee anything.

In fact, many students who attend Ivy League schools are strangely embarrassing for him — because they want their work and character to speak for themselves. Having big names on a resume can mean someone is exceptional, but it can also mean they're counting on those names to do the heavy lifting for them.

You can (and should) apply the same thinking to a candidate's specific experience. They may have managed a large team at their last job, but that doesn't necessarily mean they can do it at your company.

What's on their resume gets them the interview. It's what they say during the interview that gets them the job.

3. Don't hire someone to grow into the role

This is perhaps a little confusing because it seems to fly in the face of conventional wisdom. Shouldn't you put people in positions where they will develop better skills over time?

Of course, you are. However, yours company culture and leadership style will help the right candidate grow, even if they are overqualified when they start. And it's much better to hire someone who can destroy their position from day one than someone who will need their gear.

Don't hire someone who needs to grow into the role; hire someone where the role can grow in them. If you believe your company is going to grow (and hopefully it will) then the role needs to be able to grow in their skill set.

Let's go back to the example I presented at the beginning of this article – the candidate who was unhappy with our tech group at Square. That candidate ended up thriving in their role, even though the technology they required is now completely different. In other words, the role was eventually adapted to their abilities and gentle character.

Related: Avoid costly hiring mistakes with these five essential tips

How you hire a candidate sets the tone for your professional relationship

Many people look at whether to hire someone as a simple yes or no question, but it's much more than that. Hiring a candidate becomes the first interaction you have with a new employee, so how you do it colors the rest of your professional relationship with them.

Technical skills, strong references and growth potential are all valuable qualities in a candidate. But a person's character, accomplishments, and ability to excel are all much clearer indicators of how successful they can be.

And remember: hiring someone isn't when you stop learning about someone—it's when you start. You can get some more tips on how to build strong relationships with your team below.

Related: Be a coach, not a referee – How to be a good mentor and manager from a coaching perspective