There are various quizz-oriented websites that help you to learn while you earn, websites such as It Pays To Learn, itpaystolearn.com.
You take quizzes and then you earn money.
You can also set up your own learn while you earn projects.
For example, if you write articles for various websites, you can also include some of these articles as learning projects, articles where you have to research the information before writing the articles. You are learning while you earn.
For example, suppose you want to write an article about fashion and film. You know something about fashion and film, but you don't know all the details and all the history. So to write this article, perhaps a series of articles and a book on the subject, you begin learning about fashion and film.
You write several articles on fashion and film that you publish at Associated Content, Constant Content, Triond, shvoong, and/or other websites.
You are learning while you are earning.
You take notes and study this subject.
Perhaps you have enough information for a book on this subject. You contact a publisher that might be interested. You give the publishers your sample articles.
Perhaps the publisher offers you a constract to write a book on fashion and film, using the several articles as chapters for a booklength work.
Or, if a publisher is not interested you can publish the book yourself as a self-publication, then resubmit to publishers and/or distributors. Perhaps sale the book via affiliate marketing.
By using this technique for researching information and applying it to your writing you are learning while earning.
Also, when web content providers like Associated Content or Triond list subject areas, you can research and study those subject areas, so that you can also write about these subjects. This again is learning while earning. In addition, you can interview experts for articles and books.
