Let’s continue the vintage BMW idea. Old cars obviously require quite a lot of maintenance. Many people will buy a “fixer upper” with the intention of spending their spare time repairing and restoring it. There’s a very obvious market here: a guide to restoring different BMW models. Depending on your knowledge, you could produce detailed guides for the three or four most popular models and sell them. Not everyone restoring a car will buy them, but some probably will.
Obviously, you want the best tenants you can find. If you’ve chosen a property in a more affluent and stable neighborhood, your tenants are more likely to be responsible with your property and reliable about paying the rent. Properties in lower income areas are more likely to attract tenants that become delinquent in paying the rent, move out without notifying you, and damage your property. This is part of the higher risk of this type of investment property. You’ll end up with the expense of repairs and less income to spend on those expenses.
While building apps for Apple (or Android) mobile devices can be a lucrative way to generate passive income online, it's not as easy as many people make it seem. Beside the fact that it’s hard to get your app noticed among the millions being released every year, most people expect apps to be either free or very inexpensive. In fact, a recent study found that only 11% of apps are paid for. The number of paid apps will only decline over time as more players join the market. The key, like many of the business model mentioned here, is to be strategic and creative from the very start. There are a few ways to monetize your app and keep it free for users. Examples include advertising, premium services, and sponsors.
You know the fantasy: write some ebook (or better yet, hire freelancers in Mumbai to research and write it for you at $.20/word!) on some niche topic, set up AdWords and Facebook campaigns targeted to the right keywords (you can hire those Mumbai guys to do your keyword research too), put up a cheap landing page (with copy written by... guess who!), press "Go!" on the PPC campaign, and voilà. . . just wait for the money to roll in while you sleep!
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.