The other 10% you will only learn through your own trial and error because your personal situation, personality, and resources are different and every combination cannot be solved with a book or course. 

You, or your agent, should then review the estoppels with the respective tenants; record any missing information or variation to the information presented {this is how you find side deals or catch un-ethical vendors}; and have the tenants attest the estoppel (i.e. sign with a witness).If the attested estoppels differ from the information provided by the Vendor, you go back to Vendor to work why.

Even if it's a referral, it's truly a Trial & Error situation, keep your fingers crossed and a close eye on them at first! 

Both will allow you to go "month-to-month", propelio allows a 7 day risk free trial and I do have a discount code for realestateiq.co  - robin25p for 25% discount. 

Our trial date is scheduled for next week. 

., one slight variation.

Also, I will have to test out the free trial on Follow Up Boss to get an idea how the lead database works. $79 a month seems a little pricey though.

It's all trial and error.

There are so many variations that can lead to a successful direct marketing campaign.

We negotiate the transaction on the phone - make  a "trial offer" below what ever they are asking (to test their motivation) - we first get all the information we can; mortgage balance, current or in arrears, what are they selling for in the area, what kind of work does it need, who is on the deed, listed or not - how long - why didn't it sell, vacant or occupied.