Your first hires are the most important in a start-up. Truthfully, they should be more like business partners than workers. They should be the type of passionate, motivated individuals you trust so much that you end up calling them at one in the morning just to bounce ideas around.

As a serial entrepreneur, I can vouch for the necessity of great first hires. And with the recent launch of Open Me, my online social greeting card company, I've had a chance to revisit the early-stage hiring process and a few invaluable hiring lessons I've learned throughout the years.

Here are seven things to look for when making your first start-up hires:

1. They can light their own fire.

Self-motivated employees are worth their weight in gold. Your first hires should be fueled by intrinsic motivators and have a lengthy track record of personal motivation. Set your radar on candidates who've generated big results within your industry--whether it's through a large company or their own personal projects. A team of self-motivated employees, especially early on, is necessary for establishing an autonomous environment.

2. They'll have your back.

As I said above, because these individuals will often be more like business partners, it's essential to ensure you can trust them without hesitation. Be sure to ask the right interview questions to weed out the wrong hires.

3. Someone within your network referred them to you.

One surefire way to land start-up hires who are self-motivated and trustworthy is to reach out to your network. Someone you trust should be personally vouching for your potential employees. My first four hires at Open Me came from my internal networks, and they're an incredible team. Use your connections wisely.

4. They're sold on your mission.

It's mandatory for your first hires to share your mission and vision. They shouldn't be there just to please you or to snag a paycheck. Instead, they need to have stock in the company and the same attitude and buy-in as you. As a rule of thumb, seek out employees who have a "If this were my company, what would I do?" thought process.

5. They're visionaries who get stuff done.

Sometimes the "dreamer" types don't have a tracklist of success under their belts. That's a problem because you need someone who can demonstrate their critical thinking, creativity and problem-solving skills. In my experience, it's best to avoid hiring past executives who were managing large teams. These individuals aren't used to rolling up their sleeves and are more likely to delegate rather than get things done by themselves.

6. Thick skin is a must.

Start-ups move fast, and you won't always have time to worry about approaching every situation with care and a gentle hand. Your first employees shouldn't take things to heart. They've got to be ready to confidently hit the ground running.

I chose my first hires at Open Me because they're the best at what they do, and they know it. The team dynamic is based on confidence and trust, which means no one is fighting for project ownership.

7. Remember: Low-cost labor isn't always cheap.

Far too many founders make the mistake of hiring interns or entry-level types as their first employees. This puts you in an awkward position, because fresh employees often need more training and guidance to impact your bottom line. What founder has time for that?

For instance, you may feel like you're saving money by taking on five interns. In reality, one experienced, qualified hire can outperform all five of them.

What's your secret for making great startup hires?