Nobody gets early FI investing in bonds, CD’s, or even stocks unless they make a huge income or are extremely frugal or a combination of both. Paper assets just don’t provide enough returns. Business income can be great but it is typically not as semi-passive as I would like and there is a relatively high failure rate. That is if you can monetize an ideal to begin with. RE investing needs to be higher ranked IMO as a way that the “average guy” can become FI.
If you happen to be a photography enthusiast, consider selling your photos to stock-image websites like Shutterstock, Alamy, and iStockPhoto. The demand for high quality pictures in commensurate with the competitiveness of this business. So, if you find a niche (such as landscape photography or business photography) and establish yourself as an expert in it on even one site, you can certainly earn a lot of money in your sleep.
E-Commerce is growing on a huge scale globally, including India. It can be a source of your second income and you can earn lakhs of money on monthly basis. You don’t need a big amount of investment to start your E-commerce business. You can create your own eCommerce website without any hassles, or you can also hire a professional to create your website. Once a website is set up, invest a bit in digital marketing of your website and its products/services and you are all set! E-Commerce business can provide you with a source of income on regular basis without much effort. You do not need to set up a physical office or hire hundreds of employees unless you want to be the next Flipkart. Even a small eCommerce business can fetch decent monthly earnings without much spending or hassles.
For a person working for a wage, their source of income is their job, or their labor (aka their time that they sell to someone). But you can own a house, and rent it out, and when your renters pay you renter every month, the source of that income check is your rental property, or your house. It would just be called rental income. If you have money in the bank in an account that pays interest, those interest payments are another source of income. We can say the source is interest payments, or we can identify the asset that is generating rent, and say your money in the bank that is generating “rent” (aka interest) is your source of income.