I think the holy grail of financial freedom is having so many passive income. This way you will never worry about your financial needs because everything is taken care of your assets. You will have all the your time in the world and visit all places you dream about. You have your time and money. This is the dream of most people which only few ever achieved.

As a private lender, you can lend to anyone in your social circle. For example, many home rehabbers need access to a source of capital they can tap into very quickly in order to fund the initial purchase of their properties. You can partner with a rehabber who uses your capital for a short-term in exchange for an interest rate that is mutually agreed upon.
I agree mostly with the real estate advice. I’m looking for ways to take advantage of the condo I own to get up the rent from ~$0.90/ft to the $1.2-1.5/ft that seems more like the range in the same area. I’d have to put in a bit of capital (probably 10k on the low end for just the basics up to 40k if I wanted to remodel the kitchen and 2 bathrooms up to par with the area), so the return is likely there if those upgrades warrant $1.30/ft (given the unit is larger than most 2br/2ba in the area).
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.