If you have a knack for creating unique images, there’s no need to fuss over your own inventory. If your creations can be easily printed onto a product, then you can make money. Upload your designs on a variety of websites like CafePress. If someone likes them, the company prints them up and ships the product. You could create unique designs for calendars, books, T-shirts, bags, hats, greeting cards, or posters and get a commission for each one sold. Some of these sites include Zazzle, Teespring and Lulu.
Mobile applications are more popular than ever, with people willing to pay good money for ways to manage their lives from their smartphones. If you have a great new idea for an app and know how to code, you can run with it and create your app yourself. You can also become an app developer for businesses that need to create specific apps. Both options will require you to know the basic elements of software design and at least two common programming languages, such as SQL, JavaScript, PHP, Python, Ruby on Rails or iOS.  

One of the most important internet marketing strategies is to develop every customer's lifetime value. At least 36 percent of people who have purchased from you once will buy from you again if you follow up with them. Closing that first sale is by far the most difficult part -- not to mention the most expensive. So use back-end selling and upselling to get them to buy again: