WRITTEN BY Warren Berger

In a previous post, I shared questions that can help in overcoming fear of failure. But sometimes, there’s an even more basic problem that can stop us from pursuing bold challenges and ambitious goals: not knowing which challenges or goals to pursue. These days, you’re urged to “follow your passions” and “lean in”–but what if you’re not sure where your particular passion lies? What if you don’t know which way to lean?

This can be an issue not only for those starting out in a career, but also for some who are established, even highly-successful, yet unfulfilled. It’s easy to find oneself on a path determined by others, or by circumstance (i.e., the job offer or project that comes along unexpectedly and is too good to turn down, then becomes a career).

Whether you’re starting out or considering a possible change in direction, asking yourself the right questions is critical. The following eight–shared by a noteworthy lineup of entrepreneurs, innovators, consultants, and creative thinkers–can help you figure out where your heart lies and what you really ought to be doing.

What is your tennis ball? This question, derived from a terrific commencement speech given at MIT last year by Dropbox founder Drew Houston, is a good place to start because it cuts to the chase. As Houston explained, “The most successful people are obsessed with solving an important problem, something that matters to them. They remind me of a dog chasing a tennis ball.” To increase your chances of happiness and success, Houston said, you must “find your tennis ball–the thing that pulls you.”

Sometimes, we may not be aware of what truly engages us until we examine our own activities and behaviors from a detached, inquisitive perspective. “You almost have to ask yourself, What do I find myself doing?,” explains the author and happiness guru Gretchen Rubin. “What you spend time doing can also tell you what you should do. Because sometimes the things we do without thinking really are things we naturally enjoy or are good at.”

So pay attention to what pulls you. For instance, “when you’re in a bookstore,” says author Carol Adrienne, “what section of the store are you drawn to?” That will not only tell you what books you love–it may point to where your tennis ball can be found.

For a slightly different spin on the “tennis ball” concept, ask: What am I doing when I feel most beautiful? This is about identifying not only what draws you in, but also what makes you shine. Jacqueline Novogratz, founder ofThe Acumen Fund, told me that in her globe-spanning travels she often asks people this question, sometimes in unlikely settings. She once posed the question to women living in a slum in Bombay. At first, “one woman said, ‘There’s nothing in our lives that’s beautiful,’” Novogratz says. “But eventually, a woman who worked as a gardener said, ‘All winter long I slog and slog, but when those flowers push through the ground, I feel beautiful.’”

Novogratz says it’s important to think about “that time and place where you feel most alive–whether it’s when you’re solving a problem, creating, connecting with someone, traveling.” Whatever it is, Novogratz says, identify it–and if possible, find a way to do more of it. (A different version of Novogratz’s “beautiful” question is suggested by consultant Keith Yamashita of SY Partners: “Who have you been, when you’ve been at your best?”)

What is something you believe that almost nobody agrees with you on? This question, which PayPal co-founder and Thiel Foundation chief Peter Thiel has shared publicly in interviews and lectures, is designed to do two things: help you figure out what you care about and also determine whether it’s worth pursuing, based on uniqueness. Thiel concedes that it’s a challenging question because it can be tough to find an idea or belief that isn’t shared by many others. “Originality is deceptively hard,” he told Pandodaily.

But if you can find a problem or challenge no one else is tackling, you can carve your own niche and create value. “You don’t want to be interchangeably competing with people,” Thiel says. Though we’re taught to do what others are doing and try to succeed by out-competing, this, in Thiel’s view, amounts to “beating your head against the wall–rather than going through the open door that no one is looking at.”

What are your superpowers? The idea behind this question from Yamashita is to “unpack the combination of personality traits and aptitudes you bring effortlessly to any situation.” The filmmaker Tiffany Shlain of The Moxie Institute also explores strengths and natural “superpowers” in her new web film “The Science of Character,” which suggests that if we can identify our inherent character strengths and build on them, we can lead happier, more successful lives. Having trouble listing your powers and strengths? Check out the “Periodic Table of Character Strengths” in Shlain’s film, or refer to Gallup executive Tom Rath’s popular “StrengthsFinder 2.0” program, with its menu of 34 traits. Once you’ve identified your own strengths, you’ll be in a better position to make the most of what you already have going for you.

Sometimes by looking back into the past, says Rubin, you can get a glimpse of who you really are and what you loved doing before others started telling you what you should do.

So what did you enjoy doing at age 10? Eric Maisel, a psychotherapist and author, agrees, adding: “The things we loved as a child are probably still the things we love.” He suggests drawing up a list of favorite activities and interests from childhood–“and see what still resonates with you today. And then it’s a process of updating those loves. You may have loved something that doesn’t even exist now, or doesn’t make sense in your life now–but you may be able to find a new version of that.”

What are you willing to try now?  One of the best ways to find your purpose and passion is through experimentation. For many people, this is counter-intuitive. Herminia Ibarra, a professor at INSEAD and author of Working Identity: Unconventional Strategies for Reinventing Your Career, points out that there is a tendency to devote extensive time, research, and planning to figuring out the ideal path before taking any action. This may involve poring over self-help books, soliciting advice, and waiting for the epiphany that shows you your “true self”–at which point you can strike out confidently in a new direction.

But that’s all wrong, according to Ibarra. “To launch ourselves anew, we need to get out of our heads,” she says. “We need to act.” That means devising a series of trials and errors: Ibarra advises looking for temporary assignments, outside contracts, advisory work, and moonlighting to get experience or build skills in new industries; executive programs, sabbaticals, and extended vacations also can be valuable in providing opportunities to experiment. She concludes, “We learn who we are–in practice, not in theory–by testing reality.”

Looking back on your career, 20 or 30 years from now, what do you want to say you’ve accomplished?  In an interview, LinkedIn CEO Jeff Weiner said that he often asks prospective employees the above question. “You’d be amazed how many people I meet who don’t have the answer to the question,” Weiner said. So here’s your chance to answer it (without the pressure of having Weiner across the table, awaiting your response). Think of this exercise as a less-gloomy version of write-your-own-obit. What would you include on your list of hoped-for achievements? Or, even better than compiling a laundry list, why not figure out…

In the end, simplicity is best. What is your sentence? is a question designed to help you distill purpose and passion to its essence by formulating a single sentence that sums up who you are and what, above all, you aim to achieve. It’s a favorite question of To Sell is Human author Daniel Pink, who acknowledges in his book Drive that it can be traced back to the journalist and pioneering Congresswoman Clare Booth Luce. While visiting John F. Kennedy early in his presidency, Luce expressed concern that Kennedy might be in danger of trying to do too much, thereby losing focus. She told him “a great man is a sentence”–meaning that a leader with a clear and strong purpose could be summed up in a single line (e.g., “Abraham Lincoln preserved the union and freed the slaves.”).

Pink believes this concept can be useful to anyone, not just presidents. Your sentence might be, “He raised four kids who became happy, healthy adults,” or “She invented a device that made people’s lives easier.” If your sentence is a goal not yet achieved, then you also must ask: How might I begin to live up to my own sentence?