Whether it’s an important consumer application, a specialist app to solve a particular niche problem, or even a time-wasting game you can play on your phone, you can create a massively successful business if you build software that helps people. (Look at the rise of Slack—the team communication software that went from side project to billion-dollar company in just 2 years.)
If you have a propensity for writing and you can slay with your prose, consider writing an ebook. While the market has certainly become saturated as of late, books that help teach people about a technical topic still sell extremely well. This is a great source of passive income but does require a large amount of effort at the outset before any money is generated.
As you start regularly putting out content, you’ll hopefully start to build a bit of an audience. But to start seeing real money from YouTube you need to market your videos elsewhere. Share your channel on Twitter and Facebook. Distribute videos anywhere else you can think of. Also, interact with comments and build a community around the videos you’re making so people will share it with their friends.
Cafe Press: This website allows you to create digital designs that can then be sold on the platform. You'll earn a commission for everything that sells and you'll never have to deal with logistics like printing, warehousing and customer service. If you have some graphic design skills, then this is a great potential source for your web-based income. 
If you love to travel and find yourself randomly searching for airfare sales or browsing Lonely Planet, why not carve out a niche for yourself as a private travel agent? My friend, Mark Jackson did just that, making extra money online with his travel consulting side business. Start with word of mouth recommendations from friends who know they can count on you for the cheapest flights, and then move on and create a Facebook or LinkedIn group to invite people who want to stay on top of the latest deals. Eventually you could spin this into a full-time consultancy teaching people how to make their dream trip a reality.
You'll also need ecommerce software, fulfillment software, worry about warehousing, customer service and refunds. But that's not all. You'll also need traffic. Think search engine optimization, Facebook ads, and other social media campaigns. It is hard work, especially on your own. You could opt for Amazon's platform, which might be the easier route. But, then again, at the end of the day, this is a serious business, which could produce significant profits. So you're either all in or you're not. 
Today, if you're at all serious about succeeding in any endeavor, whether online or offline, you have to deliver enormous amounts of value. Yes, you have to do the most amount of work for the least initial return. This is especially true online. Why? Because it takes time to build authority and create an audience, two primary ingredients necessary to succeed in the wonderful world of commerce on the web.
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