One of my favorite songs is U2's "I Still Haven't Found What I'm Looking For."

I never knew what I was looking for but I stumbled onto some things I like doing. When I got to college, I wanted to be a poet. My father tells me he handed me the yellow pages and told me to look up poet -- I did not find any listings. (I do not remember this).

So I had to look for something else.

I figured out I was looking for happiness which for me flows from two sources -- adding value -- doing something well that others see as valuable -- and toy joy. How so? When my children asked me to buy them a toy, they became very happy when I agreed -- but that happiness peaked as I drove them to the toy store and began declining rapidly after the buy. Within two weeks, they were bored with the toy and their joy had evaporated.

I've gotten toy joy from lucky investments in startups -- for example, three of the startups in which I invested were acquired for a total of over $2 billion -- but the happiness from the score has been quickly replaced by a hunger to find the next one.

Adding value has been a more sustainable source of happiness. And after working for two consulting firms founded by professors from MIT and Harvard Business School, I stumbled into it when I tried teaching at Babson College.

Since I am untenured, my survival in the job -- where I have been for 15 years -- depends in part on continuing to get good student evaluations. It also depends on the opinions of the professors who run the place. I've been pleasantly surprised that they let me create new courses, value my book and column writing, and appreciate my media presence.

In short, I am in a place where students, faculty, and administrators see me as adding value doing something that I enjoy. In that sense, I found what I'm looking for.

Here are four steps that might help you find what you're looking for.

1. Know What You Value

You can't excel at any activity unless you care about it. That's because we live in a highly competitive world where only the most talented and hardest working people rise to the top. So you need to find work that passes three tests:

  • You care about it passionately;
  • You are better at it than most everyone you know; and
  • It makes other people better off enough for them to pay you to do it.

If you do not know what kind of work satisfies those three tests, you can start to discover it by knowing what matters to you. Do you care about making money above family, friends, and doing good for society? Do you long to make a contribution to society that means more than mere cash accumulation? Do you like to spend time alone thinking about the world or do you derive energy from helping other people?

If you can figure out where you stand on these questions, it will help you brainstorm possible options for your career.

2. Experiment Frugally

Maybe you are one of the lucky few who know what work best suits them. If not, come up with your three best ideas. Talk to people who excel in each of these fields. Ask them questions such as:

  • Why did you get into this field?
  • What do you like about it?
  • What do you not like?
  • What have you learned about it that you wish you knew when you started?

Such interviews can help you get a feeling for which field you might like the most. But you can't know for sure until you actually start working. And that's why you should explore a brief internship in the fields that seem most appealing based on the interviews.

3. Learn From Your Experiments

Once you've done these internships you need to take an objective look at what you liked and did not like about them. What's more you need to ask your boss at those internships for some honest feedback about whether she thinks you are cut out for this field, if so, why or if not, why not.

In my case, I decided by the end of my junior year in college that I wanted to go into strategy consulting. While in graduate school at MIT, I was able to get a job at an information technology consulting firm founded by four MIT professors.

That experience taught me that I loved working with smart people, applying great ideas, and traveling around the country consulting to bib companies. But I also learned that I was more interested in the strategy side than the systems part. So I was able to move on after business school into a strategy consulting firm co-founded by HBS strategy guru Michael Porter which better suited my interests and skills.

4. Take Advantage of Luck

If you narrow down your options by following the first three steps, you need to keep discovering new opportunities. And that comes from making your own luck -- which will inevitably produce a mixture of good and bad outcomes. You should learn from both and try to expand on what works.

One bit of luck that has really helped me out was that I decided to try to write a book based on one of the first projects I did after I started my own consulting firm. I wrote a book proposal which was rejected by Harvard Business School Publishing.

But HBS Press gave me helpful feedback which I used to revise the proposal and find another publisher which ended up publishing several of my books. And that led to speaking and investing opportunities around the world.

I've enjoyed most of the journey but if I had known about these four steps when I started, I might have found what I was looking for faster.