As my fellow Inc.com columnist Michael Simmons has pointed out, all incredibly successful people share one common trait: They're constantly learning.

Elon Musk, Oprah Winfrey, Bill Gates, Warren Buffett, and Mark Zuckerberg all make space in their super demanding schedules to ensure that each week they're just a little bit smarter than they were the week before.

How can you follow in their footsteps?

You might not have time to go back to school or read a library's worth of books, but you most certainly have time for the techniques below, which can help you keep learning no matter how busy you are.

1. Read strategically.

If you don't have hours and hours to devote to reading each week, be thoughtful about what you read. The Muse's Stacey Gawronski suggests exploring subjects outside your comfort zone. Why? "It can help you discover new interests, and once you start going down that new rabbit hole, who knows what other things will open up," she notes.

2. Retain more of what you read.

Not only is it important to choose your reading wisely, it's also important to retain as much useful insight from each book as possible. Use the three principles of impression (pausing to really visualize or understand what you read), association (connecting new content with what you already know), and repetition (rereading, note-taking, or margin-jotting) to accomplish that. Here's an explainer.

3. Talk to smart people.

This one is so obvious, but so powerful (and also so frequently overlooked). "Seeking out intelligent people and chatting them up can be eye-opening. I'm always drawn to people who are really good at what they do, and if I meet someone involved in something I know nothing about, I'm intrigued and inclined to ask a lot of questions," writes Gawronski.

4. Don't be afraid to sound dumb.

This is a corollary to point three. Making friends with smart people is a great start, but to really get the most out those relationships, you're going to have to be willing to ask some pretty basic (a.k.a. dumb-sounding) questions. That's OK! It's how you maximize learning, so put pride aside and let your curiosity lead you.

As entrepreneur Kevin Johnson says of seeking out smart people to befriend, "They make me feel inadequate and sometimes just really stupid, but I am OK with that, because I know that I learn so much from them."

5. Leverage the Web.

You already probably spend hours online. Why not get a lot more out of that time by swapping some of your social media browsing or cute kitten appreciating for a free online course, thought-provoking TED Talk, or one of the many, many other free educational sites available.

6. Leverage work, too.

There doesn't always have to be tension between time for work and time for learning. Sometimes you can further your professional and personal growth at the same time. Whether it's a formal training program offered by your employer or an insightful industry conference, opportunities to learn and work simultaneously abound if you look for them.

Even "if you work for a small employer, don't rule out the value of informal training," suggests Pick the Brain's Ali Luke. "Perhaps you can get a colleague to teach you a new software package, or maybe you can get some books on expenses."

7. Switch up your routine

The right routine can eliminate a lot of stress from your days, but sometimes what you gain in productivity and comfort you lose in creativity and learning. For that reason, if you want to be a constant learner, consciously force yourself to shake up your routine every once in awhile.

As Lifehacker's Eric Ravenscraft puts it, "Anytime you force yourself to make a change to your work flow, you encourage your brain to make new connections ... Routines can run on idle, but changing our habits forces your brain to pay attention and learn."

8. Learn from your elders.

You're going to have to attend family gatherings anyway. Why not use them as an opportunity to mine the underappreciated wisdom of your elders? This genealogy site offers a great list of questions to inspire you and help you kick off meaningful conversation. You can use them with anyone who is rich in life experience.

Would you add any other advice to this list?