Many people might argue with me on my next point, but I would suggest that you pick up some skills in the "trades" so you will learn more details about buildings and be able to evaluate buildings more clearly. 

We spent the 3rd quarter evaluating the market and houses. 

Of course the forums and podcasts are great resources, check out the "Analyze" section for some cool tools when evaluating property. 

Separate the commercial from the residential when evaluating.  

I purchased my first properties off market not too long ago and pretty much made up my own way to evaluate them.  

You need to learn how to evaluate a rental property.

I have built several log homes as well as tradition frame structures.  

Until I take my next step in REI and the majority of my business is comprised solely of assigning contracts to other private investors; I only want to be thought of or considered to be the number one wholesaler; at least in one way or another to every quality investor/professional that I have the privilege of I coming acrossI will always need as long as I am a real estate investor; all of the tricks, tools, & trades I learn through becoming a tremendous wholesalerI want every aspect of my lead generation, my property evaluations, my deal analysis, my renovation budgets (determinations, estimates, & timelines) the complete all in requirements in both time and holding cost spent from start to finish, establishing ARV’s, and of course nothing less than 100% picture perfect all-inclusive, data thorough, as easy to say yay or nay on in moment style property breakdown presentations!

I just completed a drive-by evaluation of the property and immediate surrounding neighborhood.  

I feel your pain and am a lot more diligent and no longer buy 1940ish properties at auction that I can only evaluate from the outside.As you said, painful lessons learned!