Start-up founders and employees have raw talent, but need real mentorship to thrive. Trevor Sumner offers his best career wisdom to would-be entrepreneurs.

Before processing any opinion from an "expert," you have to be cognizant of the biases that "expert" might have. So let me state mine outright: I am not a career coach, I'm a serial entrepreneur. I graduated Princeton in 1998 in an age where you seemingly had to be an idiot not to get caught up in the Internet craze. We were all going to be millionaires, you see.

But in the false promise of our irrational exuberance, I found where I did belong: start-ups. I have always worked for start-ups, eventually founding my own company, LocalVox. But they're not for everyone--they are exciting, challenging, dynamic, interesting and emotional. They breed tremendous bonds among team members.

Perhaps more than anything else, they are driven by great and often young people looking to build a career and able to take a risk early on. These are often people with tremendous raw talent in need of mentorship and career advice.

Ultimately, I believe you will excel at what you are driven by--your passions. When the gas tank is empty and it is 1 in the morning, you need to want to be there, wherever that may be. You need to make others want to be there too. So you better love what you do. A lot. So above all else, as an important litmus test, never take a job or start a company you are not excited to tell your friends about--period.

Here are three pieces of advice I've learned to take to heart:

1. It's about people. 

Although it feels like every job is the crucial next step in your career, in hindsight, it's often just one of many. That's not to say you should take it lightly, just that every gig is part of a much longer journey. It's important to be at least a little over your head in any new role. Don't worry, you'll grow into it. If you are not in over your head, over-perform and look up the organization for a better fit and start positioning yourself now.

One of the most valuable ways to accelerate your learning is to find a great mentor. Nothing substitutes for having a seasoned guide to help you understand and navigate issues above your pay grade, give you context for what you are doing and be thoughtful about what skills you need to acquire.

If you can't find a mentor where you work, find someone outside of the organization. You will find asking for help to be surprisingly effective. Be open, honest and thankful and listen for the nuggets of wisdom that will change your life.

Unfortunately, the converse of the mentorship rule also holds true: a bad boss or mentor trumps all. Be careful of bozos, psychos and those who don't really care about you. There are more of them than anyone would like, and it's too easy to pick up bad habits or, worse, accept a bad situation. Don't get trapped by inertia.

Lastly, remember that what you bring to the table in any job is more than just skills. No (wo)man is an island. You can only scale to a party of one, and the connections you bring are just as, if not more valuable than your skills. If you can connect to an ecosystem of people to better answer questions, learn best practices and drive partnerships, you are much more valuable than your skillset alone.

2. Act like an owner--become a founder.

There is a vast difference between being a part of an initiative and driving it. Are you driving forward or waiting for instructions? Are you proactive or reactive? Don't wait to be "caught" when mistakes are made. It builds much more trust to be the first to explain when mistakes are made and how to correct them.

Understand what drives the business and why what you are doing is important in that overall context. Think about what could be exponentially better for the company. Experiment. Throw around ideas. Ask. Listen.

Every business is looking for leaders. Leaders try to find creative solutions, challenge the current thinking and find ways to innovate. So should you, on your own initiative.

Being an owner also means being a positive teammate. Avoid negativity when communicating horizontally and below. Lead by example and do whatever it takes to get the job done. Over the long term, strive to become a founder--the ultimate driver. It's the richest, most challenging and most rewarding thing you can do.

3. Be really smart with your money.

Being a founder or following a career that you are passionate about may involve risk, and you need a certain amount of freedom to take it on. This is not career advice per se, but it is important to manage your spending. Your freedom is a simple equation:

(Dollars in the bank) / (Expenses per month)

And it's harder to move the numerator than the denominator. So keep your costs low, save your pennies. Stay resilient. Don't make a bad decision and end up in a passionless career because of the money. Find happiness in what you do by having the freedom to make the right choice for you over the long term.

These sage pieces of advice were collected from multiple mentors; others were lessons from challenging environments. Hopefully they lead you on a path of happiness, fulfillment and a career full of rewarding memories and accomplishments.

Trevor Sumner is the founder of LocalVox, a rapidly growing start-up in New York City that provides a software platform to help local businesses market themselves online. @TrevorSumner @LocalVox