There is a good thinker that says the neighberhood can be as important as the quality of the property that your investing in as far as value goes.Take advantage of people are more motivated and are willing to help people close.  

Here is the text that maters in your situation DEFINITIONS OF WORKING RELATIONSHIPSFor purposes of this document, seller also means “landlord” (which includes sublandlord) and buyer also means “tenant” (which includes subtenant).Seller’s Agent: A seller’s agent (or listing agent) works solely on behalf of the seller to promote the interests of the seller with the utmost good faith, loyalty and fidelity.

Start with a basic real estate text book, or a basic real estate course at a local college or through a Realtor's Association.  

I am a wholesale investor in the Houston market, I have been doing direct mail to get motivated seller leads, but I am not having a lot of response.

Someone that already works as an hourly subcontractor or maitenance person will probably be able to offer the best value if they are motivated.

In the MLS you will find every type of description of houses, for example; estate, foreclosed, vacant, motivated seller, institutional seller, REO, bank-owned, divorce forces sale, etc..  

The bank does all the keeping track of on-time or not and I get a text when the money arrives.  

It's far better to look for other triggers like foreclosure and defaulted taxes where the motivation is much clearer to all parties. 

Two minutes after that text she replied that she had the full rent.

The property does need a bit of work, and think I can get it at a discount from the motivated seller.