We realized that one would soon be unemployed due to their relocation and the other was starting grad school (also unlikely that they'll be making a meaningful amount of money).

Gut instincts of seasoned investors certain are meaningful, but to determine exactly what quantifiable data is behind a gut instinct can be very hard, if not impossible (maybe one day).Also, every investor has a different set of goals, so asking one investor where to invest (and how to evaluate it), may not get you the answer YOU are looking for.If you look at the reports that Jon and I highlighted, this will give you an idea of some of the data and trends that the big companies use -- things like employment, market rent trends, number of new starts, population trends, etc.

they are very adept at extracting every dollar possible, and leaving nothing on the table.They can work when you want to own the property to use, are willing to pay the expenses, and regard any income from renting out your unit as “found money”.

Way to general of a question to get a meaningful response. 

Because we started later, we had a meaningful amount of equity in our primary residence. 

Without having done deals, I wouldn't have had nearly as much of a reason to start and build deeper and more meaningful relationships with these types of people. 

Have an attorney review them and do not be afraid to negotiate terms and conditions - even using one contract to extract concessions from another. 3.

That's code words you tell yourself to justify not moving forward with any meaningful action.   

I cannot seem to locate this area where the author's of the articles are extracting data within …  would someone be so kind to point me in the right direction?

Skip collecting pay stubs and bank statements; those remain requirements for securing mortgage financing but employment and past landlord are more meaningful for tenant selection.