The property value must be a minimum of $250,000 USD, and the credit score requirement is at least 700 points, among other conditions.

I have them process credit card payments.

Buy quality properties in strong submarkets, finance with low leverage, bulk up on cash reserves, diversify geographically, and you'll be positioned to survive whatever the economy throws at you.

You lose because there are many other suckers out there falling for the same line and sharing the same low-quality leads that don't translate into sales.Do the math.

Locally my observation is that the need is more for low income young and working vs college student.

Most of the stuff you can get at Home Depot or Lowes and get it the next day, so no delays once you decide on something. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The other way I fund deals with none of my own money is using a private lender that I have years of experience and relationship with and/or using HELOC and other business lines of credit.

City-Data and Census.gov are solid resources, and sites like Rentometer can give you a good sense of rental prices.After that, I narrow it down to neighborhoods with strong fundamentals—good schools, low crime, and convenient amenities.

Usually of the home requires major repairs it may require a HML "hard money loan" then you refinance in 6 months on the new ARV.DSCR is also not a great avenue for low loan amounts because all loans under $125K will take a rate hit and the minimums are usually $125k after down payment with some going down to $100K Min.