You’ve probably heard about the concept of passive income. The idea is that you can earn money doing something once, then earn from it again and again without much further effort on your part. While this is a great idea, it’s not always as easy to implement as you might think. — Getting a stream of passive income is more like starting a business than getting a second job, it takes time and works to start earning, and there are no guarantees that your business will be profitable. But if you’re willing to invest in yourself and put in the effort upfront…