I have had many experiences with co-founders: I co-founded several businesses in the past, and I've been friends with co-founders of other startups

Over time, I've seen it all: From near-perfect co-founding teams to incredibly bad situations where co-founders ended up despising each other, refusing to every talk again, and even occasionally taking their differences to court. (See: Zuckerberg and Eduardo Saverin.)

But don't be too influenced by the cautionary tales. While sometimes it does make sense to go it alone, other times you really need another person by your side when you start a business. Maybe you're great at sales and marketing, and a potential co-founder is great at tech. Or maybe you bring capital and startup seed money to the table, and a potential co-founder possesses outstanding execution skills.

Just like your first hire should be totally different from you, in some ways, so should your co-founder. But not too different: You need to have the same values. A similar work ethic. A similar approach to working with people, and building teams.

So how can you make sure you and a potential co-founder are a great fit? Make sure:

1. You respect one another.

Everything starts with respect. Respect lies at the heart of any great relationship, professional or personal. While you'll share many things, you'll also be different. You'll have different skills, different experiences, different strengths and weaknesses.

You might not even be friends. In fact, you don't have to be friends.

But you must respect each other, because respect lets you look past the ways you may differ to see the value you each provide to the business. A shared vision is important, but a shared sense of respect matters more.

2. You understand and know how to work with each other's strengths and weaknesses.

As the months go by, and the stress of starting a business piles up, it's easy to start underestimating the importance of your co-founder's skills and overestimating the importance of their weaknesses. If you're great at sales and your co-founder is not, that can start to seem like a huge problem -- even if your technical skills are poor and she's the one making all your startup trains run on time. 

Identify not just complementary skills but complementary weaknesses. Determine how your different strengths will help overcome your different weaknesses. You don't have to be great at everything as individuals (in fact, you shouldn't be) but you do have to be great as a team. 

3. You expect to manage money in a similar way.

Nearly 25 percent of small businesses fail because they ran out of money. Sometimes that's because they were under-funded in the first place. But sometimes that's because the co-founders had different opinions on how to manage the money they did have.

For example, say your startup is struggling to generate revenue. You might think cutting advertising spending is the right answer. Your co-founder might think cutting marketing costs, especially when you desperately need new customers, is the last thing you should do. (In most cases, your co-founder is right.)

Or your co-founder expects to have a nice office, while you feel like your kitchen table is the perfect place to start the business. Or you expect to draw a salary right away, while your co-founder feels using that money to hire one or two key employees makes better sense. 

You'll need a shared vision for how you'll budget and spend money, especially if you bootstrap your startup. Which raises a larger point:

4. Your long-term vision for the company is similar.

Starting a business with the intent to sell as soon as possible is different from starting a business you hope to run for decades. 

At the very least, if your co-founder expects an early exit and you do not, make sure you provide for that contingency in your partnership agreement. You both need to agree on what you hope to achieve and how you hope to achieve it while recognizing that plans will change. In a startup, things always change.

5. You both listen well.

Many people talk well. Fewer listen well. Make sure your partner is genuinely curious, wants to know what you think, and is more concerned with finding out what is right than being right.

Make sure you are, too.

6. You fight well.

Disagreements are normal and healthy. In fact, if you never disagree, maybe you haven't found the right co-founder.

Make sure that when you do disagree, you are able to listen to each other's points of view and find common ground -- or at the very least do the right thing for the business. Being right doesn't matter. Doing the right thing does

7. You've tested out the relationship.

A lot of work goes into starting a company before you actually start it.

Use that time to work with each other before you incorporate: Developing a minimum viable product, developing a marketing strategy and finding your first new customers. Find out, in the real world, how well you work together.

Plans are great, but execution is everything: Not just in business, but also in a co-founder relationship.