Reid Hoffman, investor and co-founder of LinkedIn, and Ben Casnocha, entrepreneur and author, share valuable tips on cultivating and seizing make-or-break opportunities.

Success begins with opportunities. But not just any old opportunity will do. Entrepreneurs don’t just start any business; they seize the great business opportunities. Success for a startup is all about seizing those unusually consequential opportunities — those breakthroughs, deals and discoveries that rocket their company forward at an accelerating rate of growth.

Careers, like startups, are also punctuated by breakout opportunities. Our professional lives are not a sequence of equally important jobs. There are always breakout projects, connections, specific experiences and, yes, strokes of luck that lead to unusually rapid career growth. Here are some tips for finding and generating those kinds of breakout opportunities. These work equally well for a startup as they do for an individual’s career.

1. Brim with curiosity. There’s one disposition and mindset that must be “on” like electricity to power all the other opportunity-seeking behaviors: curiosity. Entrepreneurs are perpetually curious: They see opportunity where others see problems — while others simply complain, entrepreneurs ask, Why? Why the heck doesn’t this annoying product/service work as well as it should? Is there a better way? And can I make money off it? You could even say that entrepreneurship begins in frustrated wonderment!

For you in your career, curiosity (with or without frustration) about industries, people and jobs will make you alert to professional opportunities. Ask the most curious person you know out to lunch, and try to get infected by his or her sense of awe.

2. Court serendipity. Serendipity is the delightful word we use to describe accidental good fortune. But serendipity doesn’t mean blind luck. The most valuable opportunities won’t just fall into your lap. You need to be in motion, spinning a web as wide and as tall as possible in order to catch any interesting opportunities that come your way. You create accidental good fortune by being open to potential opportunities and acting on them. So set aside one full day coming up to be a “yes day.” Say “yes” all day and note the serendipity that comes of it.

3. Cultivate randomness. It’s easy in hindsight to attribute breakthrough career opportunities to a master plan. But what more often happens is that you stumble upon the person or idea that leads to the opportunity without specifically intending to.

The key, then, is to raise the likelihood that you stumble upon something valuable by stirring the pot to introduce the possibility that seemingly random ideas, people and places will collide and form new opportunities. Try reading a book you wouldn’t otherwise read, taking a co-worker in a different department out for lunch, or attending a speech or seminar in a different but related field.

4. Connect to human networks. Opportunities do not float like clouds. They are firmly attached to individuals. If you’re looking for an opportunity, you’re really looking for people. If you’re evaluating an opportunity, you’re really evaluating people.

So identify the people in your network who always seem to have their hands in interesting pots. Try to understand what makes them hubs of opportunity, and resolve to meet more people with those characteristics. Start your own group or association. Maybe a regular luncheon or simply a one-time meetup — what’s important is that you try to convene friends to share ideas and resources. Set up a simple wiki or use LinkedIn Groups or Events to organize and share the details.

5. Take intelligent risks. Risk tends to get a bad rap. We associate it with things like losing money in the stock market, or riding a motorcycle without a helmet. But risk isn’t the enemy — it’s a permanent part of life. And taking intelligent risks is a prerequisite for seizing those breakout opportunities that cross your path. This doesn’t mean you should jump at the obvious high-risk, high-reward opportunities. Instead, pursue opportunities that have a lower risk than your peers believe, but which are still high-reward. Make a list of risks that are acceptable to you but that others tend to avoid, and go for them.

This article is excerpted from Reid Hoffman and Ben Casnocha’s best-selling book, “The Start-Up of You.”