What are some of the signs that the property could be a diamond in disguise? 

Probably the closest one for you would be the Black Diamond meeting in Worcester (2nd location in Waltham) which you should get out to.  

@Derek Diamond While I can't say my results are typical.

If you are willing to go 50-60min for any of these then I'd also say check out the Black Diamond meeting in Waltham, MA which is very good.  

Other good ones to look into are the Black Diamond meeting in Waltham (2nd location in Worcester) and @Justin Silverio 's quarterly meetup in or around Woburn.  

I'd also recommend trying to get up to the Black Diamond meeting in Waltham (2nd location in Worcester).

Black Diamond just had an attorney speaking on exactly the topic you are discussing. 

I'd also highly recommend getting down to Waltham for the Black Diamond meetings (2nd location in Worcester).  

I've got some properties in the Cleveland area and I tend to stay out of the city, but won't completely disregard it as there can be some jewels in the rough in the city(won't call them diamonds cause its not a lot of money, but any money is good money!)

You should also look into going to the Black Diamond event in Waltham (2nd location in Worcester) and @Justin Silverio 's quarterly meetup in the Woburn area.