Systematize everything from rent collection to record keeping, there are many online softwares that can help you out with this.Hope this was helpful!

It is a book based on research that he and his team performed to let only data speak and not their personal views.So in the first three chapters, some big things stuck out to me.1.

trulia.com - look at crime rates, street views of properties, GIS driven data for house values, previous price pointsrentometer.com - use free searches to determine average rent in an area based on the address and number of bedroomsIs the property generally rentable or sellable in that area?

Tax assessor values are for the purpose of collecting taxes. 

Collect monthly interest on the 750K monthly until they pay it off.

Get some more data in your system so you can actually see if its working(compare round to round).

@Jorge De Jesus I love the idea of collecting more rent for the bigger unit.

Doesn't matter how good the numbers look if you can't collect rent or find a tenant. 

Further, tracking down npn in bulk, analyzing thousands, buying packages, reselling some, working on getting the remaining reperforming and foreclosing and then disposing of the rest is far different than analyzing two or three performing notes offered by a note broker and purchasing one or two and collecting monthly payments until they are paid off. 

If the tenant refuses to pay, you can certainly send them to collections and it will sit on their record for others to see.