During my first year as a financial advisor, I got a small base salary. After that, it was up to me to figure out how to find and retain new clients. Fortunately, I quickly learned how to market myself, meet new people, and set myself up for success. And over time, I made the connections I needed to grow my base of clients, earn a real income, and produce the type of results my clients wanted.

This is an interesting take and good advice for those who probably do not need to ever worry about becoming destitute. I’m sorry but too many of your options including your own list of income require quite a bit of initial investment/capital and these suggestions are useless to those living paycheck to paycheck. I’d like to see the average low to middle income household purchase additional property for rental, invest in their portfolio (if they can even start one), or even afford to have a vehicle or room to rent. Far too first world of a solution for the general public.
Income from the performance of services directly related to the use of a vessel or aircraft is treated as derived entirely from sources in the United States if the use begins and ends in the United States. This income is subject to nonresident alien withholding if it is not effectively connected with a U.S. trade or business. If the use of a vessel or aircraft either begins or ends in the United States, refer to Transportation Income in Publication 515, Withholding of Tax on Nonresident Aliens and Foreign Entities.

Case Schiller only tracks price appreciation of RE. RE as rental investment vehicle is measured primarily on rental yield or cap rate or some other measure. Price appreciation in that scenario is only a secondary means of growth, and arguably should be ignored as a predictor of returns when deciding on whether or not to invest in rentals. More important key performance indicators for rentals are net operating income and cash ROI. Appreciation, if it occurs, is a bonus.

We’ve discussed how to get started building passive income for financial freedom in a previous post. Now I’d like to rank the various passive income streams based on risk, return, and feasibility. The rankings are somewhat subjective, but they are born from my own real life experiences attempting to generate multiple types of passive income sources over the past 16 years.
It is always fun (when things are going well!) to look back at the various streams to see what’s working and what’s not. I found that a lot of my angel investing just wasn’t working well, fortunately it wasn’t a lot! Side businesses are always nice, vs. pure investments, because of actual control. Plus you can shut it down if things go south… hard to tell someone (and convince them when you’ve only kicked in a few bucks) that it’s time to close up shop and return some capital.
These days, low-risk bond yields aren’t enough to meet most income needs. When investing in bonds, the income typically comes as coupon payments – contractually guaranteed interest payments at predictable intervals.  There are many kinds of bond income available, so you must strike a balance between reaching for higher income (yield) and limiting risk.