"Intellectual growth should commence at birth and cease only at death," Albert Einstein once said. Or, as Eartha Kitt once put it, "I am learning all the time. The tombstone will be my diploma." The pursuit of learning should indeed continue throughout our lifespan—it's an apprenticeship that never ends.

No matter at what stage in life you are, it's important to continue to sharpen the saw. That's because knowledge today has a short shelf life. Sitting on your laurels with what you learned long ago and trading on old knowledge are both surefire ways to get run over by others in your field.

Fortunately, we live in an era where there are unlimited opportunities to gain new insights and stay ahead of the curve. Opportunities for innovative learning are as close as a mouse click away.

Here are ways you can expand your knowledge and learn from the ideas and experience of others.

Sharpen Your Business Acumen

Recent research on startup failures reveals that 55 percent of all businesses fail by year five. Major causes include incompetence and lack of managerial experience, which lead to management mistakes.

Don't let this happen to you. Instead, get the expertise you need to develop and grow. My Own Business provides free courses taught by successful business owners who will point out avoidable mistakes. And at Alison, you can access a wealth of free, useful courses that even lead to a diploma in business management and entrepreneurship. Saylor Academy is another among many institutions that offers a free, extensive Small Business Management course.

Many top universities even offer online MBA courses for free. Check out how one resourceful entrepreneur is pursuing an online MBA degree for less than $1,000 by taking advantage of these mostly free courses.

Develop Your Staff

The rapid changes in the nature of work call for a nimble, skilled and knowledgeable workforce. As a business owner, one of your primary responsibilities is to create a learning environment for your staff. As leadership expert and lecturer at the MIT Sloan School of Management Peter Senge puts it, be "the leader as teacher." Foster learning for everyone in your company, and encourage their development and growth.

If your training budget doesn't allow you to send people to expensive courses, you can still find ways to provide free or low-cost training. The possibilities for Internet learning are endless. For instance, try checking out MOOC List for open, no-cost or low-cost online courses offered by some of the best universities and other entities such as Coursera and Udemy. Also look into the more than 1,500 free video tutorials in management training at Lynda.com. You can go further by making use of Degreed, a site that gives learners the tools to track, organize, share and validate everything they learn, whether it's from courses, articles, books and videos.

Become a Voracious Reader

Reading is one of the shortest routes to acquiring knowledge, gleaning deeper insights and learning from others' expertise and perspectives. Surveys suggest that CEOs of Fortune 500 companies read, on average, five to six books a month. Charles Munger, who is Warren Buffett's right-hand man, had this to say about reading: "In my whole life, I have known no wise people (over a broad subject area) who didn’t read all the time—none, zero." Good, old-fashioned reading is a powerful tool for personal and business success.

There are many avenues to use to help you choose which books to read. For example, you can subscribe to online communities like Leadership Now or 800-CEO-Read. You can also scour the Internet for book recommendations from reputable sources such as Stanford University. Here's one of their recent recommendations: "10 Business Books to Read in 2014."

If your time is limited and money is tight, subscribe to a business book summaries service such as Soundview Executive Book Summaries or getAbstract, just to name a few.

Vary Your Learning Medium

A mix of learning media may provide you with greater variety and encourage you to make time for learning. If you're more of an auditory learner, for example, consider the many free podcasts available. Here's a link to the top ranking podcasts in business. Or you can expand your mind by listening to Stanford's Entrepreneurial Thought Leaders or Stuff You Should Know.

If you're more of a visual learner, you can tap into the YouTube Education Channel, watch the Khan Academy "Interviews with entrepreneurs" or enjoy the extensive Harvard Business Review video collection. 

Broaden Your Learning

It's safe to say that many of us pursue learning that's most often within our own field. But learning from different disciplines inspires us to see our world with new eyes, which can lead us to bring in innovative ideas outside our own walls. And the more varied your knowledge, the more sources you can draw from.

Here, too, free or low-cost online learning resources abound. For example, you can learn to play an instrument, speak a foreign language or take better photographs. You can also learn about literature, psychology or programming. The range of possibilities is wondrous.

Cultivate a Beginner's Mind

"In the beginner's mind," Zen master Shunryu Suzuki said, "there are many possibilities, but in the expert's, there are few." When we approach interactions with others with a beginner's mind, we are open to learning from what others have to offer. It's a wonderful space to be because it allows us to keep our ears open and not be deaf to all the learning that surrounds us. This is perhaps what poet Alexander Pope meant long ago when he said, "Some people will never learn anything ... because they understand everything too soon." To cultivate a "beginner's mind," encourage those who disagree with you and listen to what they have to say. They might be your best teachers. Can you honestly say you learned a lot from those who agree with you?

Lifelong learning is a path to discovery and personal growth. As information economy expert Stan Davis put it long ago, we should view education as K through 80 not K through 12. And with today's abundant offerings, there's no excuse for not being a lifelong learner.

What new things do you want to learn for 2015? Share with us in the comments below.

Bruna Martinuzzi is the founder of Clarion Enterprises Ltd., and the author of two books: Presenting with Credibility: Practical Tools and Techniques for Effective Presentations and The Leader as a Mensch: Become the Kind of Person Others Want to Follow.

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