Running a startup is one of the hardest things you'll do so it's almost always better to have a committed partner that you trust to build your company with. Keywords: committed and trust.

I met Melanie, a NYC based jewelry designer, not long ago and her experiences are a prime example of why it's so important to know exactly who you're doing business with.

After working on her business for two years she decided to expand into a storefront with a co-founder. They went through the normal process of raising capital and settled on a large business loan that she was the personal guarantor for since her partner had bad credit.

Big mistake.

When the business began to be slow her partner skipped town, leaving her with all of the debt and responsibility. Technically, he wasn't liable for anything but this isn't something you'd imagine a co-founder would do, especially after so much blood, sweat, tears and money has been put into building the business together.

If you're a solo entrepreneur finding a co-founder is no small feat. It's just like looking for a wife or husband and, to be honest, you should approach it just as seriously. After all you'll be spending a lot of time with this person over the course of the next several years so basic skills like good communication, commitment to the business, and trustworthiness are all important characteristics that you'll want in your co-founder.

You won't be able to find these things out from hanging-out with your potential new partner once at a startup event.

Too often, entrepreneurs are rushing into co-founder relationships when they should be "dating" potential co-founders to make sure they find the best fit. Here are 3 ways to have the best co-founder relationship:

1. Date, date, and date some more.

?The more you date co-founders, the better. Working with potential co-founders is a good way to figure out if your skill sets complement each other or if you're duplicating skills.

Launching smaller projects is a good way to test the working relationship before you go all in and commit. Also, it's important to see how your potential co-founder handles personal relationships as well. Is this person trustworthy in their personal life? If they aren't chances are they won't be in business either.

2. Make sure you co-founder has skin in the game.

Part of the point of having a co-founder is so that the work (and stress) doesn't just fall on you. Your co-founder needs to have as much skin in the game as you and have the same work ethic as you.

If you find yourself working more, worrying more about key business decisions while your co-founder is floating through life, he might not be the best choice.

3. Consider a co-founder prenup.

This is a term that has been thrown around for the past couple of years. Basically, it's good for setting your company up the right way so that, if things don't work out, breaking up is easier to do. Not to mention ironing out what-if scenarios ahead of time.