I spent most of my career working as a psychotherapist but I always had a side hustle. My favorite side hustle was a drop ship jewelry business. I sold high-end necklaces, earrings, and bracelets without ever physically handling the products.

I was excited to jump out of bed every morning to see how much money I'd earned in my sleep. I thought it was amazing that I could sell products that I never had to physically handle. It required zero upfront investment.

I loved being an entrepreneur but for a long time, I thought I needed to sell a physical product to make money online. But in 2013, I wrote an article that went viral (50 million people read it) and I realized I could make a lot of more money selling my knowledge.

It became clear that there were endless opportunities to make money based on what I knew. I created several different revenue streams. Some of those streams include physical products (like my books) and others included services or digital products.

So whether you're a real estate agent, a plumber, or a CEO, here are seven ways you can earn a living off your knowledge:

1) Write articles.

Starting a blog might help you earn ad revenue (eventually). But, the likelihood of creating a million dollar blog is pretty slim.

You're better off writing articles in exchange for payment. There are many magazines and high-end websites who are willing to pay for your content. Some pay by the page view and others offer a flat fee.

2) Write a book.

While some people insist a self-published book is the way to go, others find traditionally published books are more lucrative. Of course, it depends on your topic.

If you have niche that isn't going attract a wide audience, you may need to self-publish. Then, it's up to you to decide whether to create a $50 manual or a $l.99 eBook.

If your book is likely to appeal to the masses, a traditional book might be a good option. The advantages of a traditionally published book include earning an advance (a set amount you'll earn regardless of how many copies sell) and royalties and the publisher pays for editing, book design, and printing fees. You'll also have professional publicists and a marketing team to assist you.

3) Create an online course.

You can create a course to host on your own site, put a course up on a website like Udemy, where you earn money on each course that's sold. You could also build a course in conjunction with a company like The Great Courses, where you could earn an advance and royalties.

You can also create a course that you host on your own website. You'll retain all the earnings for your sales, but of course, you'll need to drive the traffic.

If you've got a course that will appeal to specific companies or industries, you may be able to get a licensing deal.

4) Provide coaching/consultation.

Offer one-on-one coaching to people who want your guidance. Or, offer group coaching to people who are looking for affordable help. You could also consult with businesses or organizations that could benefit from your expertise.

5) Give talks.

Public speaking can be a lucrative source of income--if you can break into the field. Whether you're a motivational speaker who gives 60 minute keynotes or you're a trainer who offers full-day workshops, there are many opportunities for public speaking.

6) Develop a mastermind group.

Charge a monthly or annual membership fee to become part of a mastermind group. You might offer regular webinars or exclusive content as well as an opportunity for members to connect with one another.

7) Host an event.

Whether you offer a small retreat at a luxury resort that features your content only, or you partner with several other people to offer a conference at a hotel, a big event could be an excellent source of revenue.

How to Get Started

One of the best ways to start testing your ideas is to start putting content out into the world. Start a podcast or a blog, share your ideas on social media, or create videos about your subject. Once you attract interest in your ideas, you can begin developing products that will help you earn money from your knowledge.

Published on: Dec 5, 2018
The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.