One of the best parts of being an entrepreneur is that you get to decide whom you work with.

Besides personal and financial freedom, this was why I was drawn to entrepreneurship. Before I founded SalesFolk, I had worked a number of jobs that had made me extremely unhappy, partly because of the behavior, work ethic, and attitudes of the people I was working with.

I relished the idea of being able to set a more positive work culture and choose peers who would share my drive, ambition, and ethos for delivering high-quality work.

When I started my company in 2014, I believed that the key to picking the best colleagues was their intelligence. I assumed that if I hired the smartest people for my company, we'd have enough brain power that we could solve any problem and accomplish anything.

But I was proved wrong.

Since starting SalesFolk, I've interviewed thousands of people and hired some amazing people who still work with me, but I've also made some huge hiring mistakes that I had to correct the hard way. The crazy part of all of this is that some of the people I was most excited to hire became complete disasters.

Looking back on my decisions and assumptions, and how they played out in reality, I have learned a few things about what I want to hire for and what to avoid at all costs.

Let me share some of these lessons with you so you can learn from my mistakes.

1. The smartest person isn't always a good hire.

Some of my worst hires were truly brilliant. And this made getting rid of them really hard, because I liked them a lot as a people, but they had terrible attitudes and really didn't do their job well.

This became crystal clear after I started to hire more people, and I saw the difference between them and their peers. Objectively, they may have gotten a higher score on an IQ test, but they often acted entitled or were condescending to people they interacted with at work. I also began to realize that there are many different kinds of intelligence, and that the nice girl from the Midwest might actually have much higher EQ (emotional intelligence) than that summa cum laude from Berkeley. And that counted much more.

2. Always look for humble.

This goes back to the issue of entitlement. It's perfectly fine for people to be confident in themselves, but there's a difference between having a healthy self-esteem and the hubris that often becomes complacency.

When hiring someone for customer relations, I interviewed more than a hundred people for the role, but only one of them struck me as humble. Until then, I didn't feel like anyone I had talked to was quite what I wanted, so when I finally found someone who was truly humble, I hired that person immediately. And that turned out to be one of the best decisions I ever made. Now I make humble a top hiring criteria for all roles at SalesFolk.

3. Pay attention to those who are always improving.

Early on, one of my CEO friends told me that finding great job candidates is about spotting trends. They said that "career trajectory," meaning how your career is progressing over time, is one of the biggest indicators of ambition and drive.

I tend to agree, but not always; not all great candidates have perfect resumes, especially if a major life event has temporarily thrown someone off this trajectory, like the death of someone close, the illness of a loved one, or turning points that lead people to switch industries. Beyond a resume, what I'm really looking for in an interview is the desire for improvement. Startup CEOs need people who can grow with their business, especially in the earlier days. Some signs to look for in hires are that they never stop learning and they're always looking for new and better ways to do things, whether that's saving time or making more money.

4. Go for people who can get anything done.

The problem with really smart people, especially those coming from academia, is that they love thinking and talking about ideas. Sometimes a great idea can change everything for your business, but most of the time execution is a lot more important, especially for small startups.

Aside from asking people about their past accomplishments, the two traits that I'm really looking for are resourcefulness and determination. With those two things, you really can get just about anything done.