The capitalization rate approach to real estate valuation is much more straight-forward but may not give you a true market value. The cap rate is simply the annual net operating income (NOI) of the property divided by the cost or value. Net operating income is the amount left from rents after all expenses are paid but before taxes and interest payments.
The challenge I’m facing and, I know it’s a good problem, is that the SF real estate has shot up about 35% in the last couple years. I’m sure you’re experiencing the same thing! So as the net worth is rising, the yield on the total portfolio is going down. Right now, it seems the only way to increase the passive income will be to raise the rent in December and to invest some of that cash in stocks, which I’m nervous to do in this market. Current allocation:

Well written piece, but I question the core premise. Why the fascination with maximizing “income” (passive or otherwise). Shouldn’t the goal simply be to maximize long-term after tax growth of your entire portfolio? If this takes the form of dividend paying stocks, so be it. But what if small caps are poised to outperform? What if you want to take Buffet’s or Bogle’s advice and just buy a broad market index like the S&P 500, (no matter what the dividend because you’ll just have it automatically reinvested to avoid the transaction fees).
Do you have stuff in your basement, attic or garage that's collecting dust? If you do, pack up the SUV or car and kids and go to a flea market. You could make a couple of hundred, even thousands, of dollars, depending on what you're selling. You'll want to go to flea markets every weekend or at least every other weekend. Make an event out of it, and show your kids how easy it is to earn money selling their stuff.
However, when you lack the money, you need time. You'll need to invest the upfront time now in order to reap the benefits of automatic income later. It just doesn't happen overnight. So don't expect it to. However, you can do this without quitting your day job. All it takes is some sincere effort over a consistent period, and voila! But, to get there, you'll need to consistently burn the midnight oil or get up at the crack of dawn. Your choice.

Renting value is exactly what you do when you go to work every day. This is a great way to adhere to our rule against one-time consumption, although you can only rent something to one person at a time (drawback). By renting something, I can generally avoid degradation of the value, or at least lessen it. By renting you a house, I’m charging you for the value of the shelter and comfort, and in fact incur pretty minimal decrease in value as your usage of the house causes wear and tear. When you’re done renting the house, there’s still plenty of value left to rent out, and the fact that you’ve enjoyed a year or two of value doesn’t much matter to the next willing consumer.

If retirement is a goal of yours (and who doesn’t want to retire someday?!?), it’s important to learn how to start investing. In fact, funding your retirement accounts should be at the top of your list. While these accounts won’t help your immediate situation, by stashing cash now, the residual income they create should help propel you through your golden years.
To save time and effort, a person can group two or more of their passive activities into one larger activity, provided they form an "appropriate economic unit." When a taxpayer does this, instead of having to provide material participation in multiple activities, they only have to provide it for the activity as a whole. In addition, if a person includes multiple activities into one group and has to dispose of one of those activities, they’ve only done away with part of a larger activity as opposed to all of a smaller one. 
I truly believe generating $10,000 a year online can be done by anybody who is willing to dedicate at least two years to their online endeavors. Here is a snapshot of what a real blogger makes through his website and because of his website. Roughly $150,000 a year is semi-passive income followed by another $186,000 a year in active income found through his site. Check out my guide on how to start your own blog here.
Even if each patron only contributes a very small amount each month, it can still be a huge source of income. Take a look at the Patreon page for Kinda Funny, an internet video company. They have over 6,209 patrons which means an average of just $3 a month would be a monthly income of almost $19,000 – plus they get cheerleaders that are always happy to spread the word on their brand.
You can upload a T-shirt design with Amazon Merch and earn a percentage of each sale. If you choose to outsource the design, there are sites like Fiverr and Upwork with freelancers that can provide designs as low as $5 and up. Or you can buy pre-packaged designs from companies such as Design4Dollars and Merch Ready Designs, Lindsey says. also allows you to stream your own video game, talk shows, and other creations for income.
I actually spent a year and a half working as an affiliate marketer (mostly selling drumming related products – lessons, kits ect). 5 years on and one of my one page sites (which I’ve not touched) still nets me about $150 a month. I won’t be retiring off that but only really now appreciate the reverse pyramid approach to entrepreneurship (working for nothing initially but later being paid without effort!)
Your best deals, but the most work, will come from properties not formerly listed as for sale. Contacting the owners of abandoned or run-down properties might uncover a deal without the hassle of competition from other investors. Once you have the address of a property, find your county assessor’s page on the internet for ownership information. The assessor’s page will have other useful information like previous sales and house characteristics.
Most people who set up passive income don’t do it so they can lay on a beach all day, or even so they can spend their time learning a third or fourth language (ok, maybe I’m doing that), or living on private islands. No, the point of passive income is to liberate your time for more fruitful endeavors — whatever those may be. If you have the ambition and gall to get out of the “9 to 5 game” and set up passive income, chances are you won’t be happy with sitting on your butt or traveling year round. You’ll want to do something with meaning and purpose.
If you’ve ever thought to yourself, “I wish there was a product that did this,” then invent it! Create a product, medical or otherwise, and sell it as a company or get royalties for it. It’s not impossible to figure out, I have many friends who have taken a concept to market. Don’t overlook an invention as a fantastic means of attaining passive income.
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.