What I Do: I’ve set up multiple investment accounts outside my main operations bank that deals with working capital e.g checking, paying bills. By transferring my money to a couple brokerage accounts and two other banks as soon as it hits my main bank I no longer have temptation to spend on frivolous things. As a result, I can wake up 10 years later and reap the rewards of compounding. My 401(k) is the best example where constant contributions over 18 years has grown to over $500,000 without any savings pain given it just became a part of life. Real estate is also a fantastic asset class for the long term. It’s fantastic to enjoy your home, pay down your mortgage each month, and end up with a paid off asset that has likely appreciated during your time of ownership. 
Venture debt ($12,240 a year): The first venture-debt fund has returned almost all my initial capital, so I decided to invest $200,000 in the second fund. I took a risk investing $150,000 in my friend's first fund, so I'm hoping there's less risk in the second fund, given he has four more years of experience on top of his 12-plus years of experience running a venture-debt portfolio for another company.
You also get to see specific details about each loan, including what the borrower is using it for, the state they live in, how long the pay-off period is, what the monthly payments are, and what rate the borrower will pay. It helps you get a better picture of what type of risk you’re exposing yourself to, and you get to take more control over your investment.
This is a venture that is growing rapidly. You can create videos in just about any area that you like — music, tutorials, opinions, comedy, movie reviews — anything you want . . . then put them on YouTube. You can then attach Google AdSense to the videos, which will overlay your videos with automatic ads. When viewers click on those ads, you will earn money from AdSense.
Build an investment portfolio that pays out dividends (Stocks / Bonds / Mutual Funds). Dividends are payouts that companies give to their investors as a portion of their earnings. They’re often paid out quarterly. If you’ve already got an investment portfolio, it’s time to take a good look at which stocks, bonds, or mutual funds you own. You’ll see consistent returns from the ones that pay dividends. This is a fantastic way to earn passive income. Invest once and watch the returns pile up.
Whether you know how to flawlessly apply eye makeup or build a wooden shelving unit, you can create an online course or video for others to follow. Websites like Udemy and Teachable allow you to build a course, such as how to learn a new language or write a cover letter. Once you build your course and set the price, there’s little work to be done. You’ll receive residual income from each person who signs up to take your course.

In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.