One of the most common mistakes beginners make is jumping into large rehab projects without having a solid team or boots on the ground. 

Most of the methods are for advanced investors and not nearly as common or easy as portrayed by YouTube gurus selling courses for a living.

Avoid common pitfalls like underestimating costs or tenant management challenges by planning conservatively and staying proactive.

A common bit of advice seen on this site is, "Don't spend $20K on a mentoring program when you could spend that money on your first deal and you'll learn much more."

More common is you move into bigger, more expensive homes that you buy, or perhaps downsize into a home without a mortgage.

Real estate's "gross rent multiplier" is Wall Street's "sales to revenue",  "cap rate" is roughly "P/E ratio".When evaluating markets and investments I tend to start with GRM (or lazily the 1% rule), then attempt to return a cap rate based on assumptions about costs, then I work my way to multiple years of projections (assumptions about inflation, amortization, tax benefits, etc), and if I am partnering with one of my smart friends I have to pull up an IRR (internal rate of return).I also look at regional employment levels, median income to rent ratio in the zip code etc. 

Just use common sense.When you get a request that asks if it is available when a quick look at the calendar or the inquiry show it is available then you should be on the look out.

On the OR Coast the regulations have grown 10X in the past 5 years, but there is still significant opportunity, particularly for initial owner/operators. 20%+ CoC is still quite common for premium Coastal STR's. 

I don't see the value there....paying a plumber to come re-iterate common sense. 

Yes, window treatments are a common one for tenants to break.