The easiest way that I have found over the years is to simply ask other investors, specifically in your local market.

You typically do not bring your broker unless they bring you the deal, and if they do that sometimes you may have to comp them When you put in your offer, you simply state the offer is based on financials provided.

Every time a guru “education” course was co pleated, I’d receive 10 -20 phone calls from either investor wannabes “building their team” in preparation for all the real estate “great” deals they were going to uncover or the same wannabes who had already identified a “great” deal (they hadn’t submitted let alone secured acceptance of an offer yet) and were lining up their financing which since they were purchasing at 50% of the value they’d end up with not only 100% financing but also walk away from the closing table with cash in their pocket.  

The company that serves and blessed me over and over again is what you would call a Tax Advisor, not simply a CPA or tax preparer. 

You can identify the hotspots for crime, school levels, income levels, where there is dilapidated homes, then based on the age and condition of the property gauge where the property stands in class, happy to talk further. 

Unfortunately having title issues is one of the reasons that sellers are sometimes willing to do seller financing simply because they know mortgage companies won't approve without proper title work and title insurance so they have to be more creative in the ways they sell but that can be risky for you as a buyer.If you do seller finance I recommend having very specific terms on HOW payments will be made and accepted and using a professional service like https://www.agecroftcapital.com/ for loan management in the case of any disputes - just my personal rec, not sponsored by BP though I do work for BP :)

Is there a business you can simply push up and increase revenue by a lot to produce the money you want to invest? 

@Maria Murphy yes correct, simply paying the debt in the owner's name to hacienda (tax office)/government first as part of the purchase at the notary and everything left to the seller.Valencia has worked quite well for us the last years and compared to Barcelona/Madrid the m2 prices are a lot lower.

Identified two properties zoned, for sale and price is right.  

After 5 years and very little progress on the ADU valuations I suspect the ADUs simply do not have a value equal to the small unit, small count cost and never will.