This simply comes with looking at countless deals in a specific area systematically.  

I have spent countless hours trying to research my options online without much luck.

I've read countless personal finance/investment books that all seem to say the same thing (not to imply this information isn't valuable).  

That mentor will save you countless hours of trying to learn everything yourself.

So far I've read several books on Real estate and watched countless videos of Biggerpockets and several others as well.

I have purchased countless houses by recording an address and sending a letter. 

I'm sure there are plenty of honest & intelligent people giving their input in the countless threads similar to mine where new investors are asking where they should look.  

However, for a market specifically like Boston where there are countless large companies and new jobs being created in the area it will keep the market stable (for purchase prices) and it will increase the rent price to where they need to be to support them).

I've been reading up and doing my homework but I have no experience in real estate unless u count countless hours watching HGTV on the couch.

Driving some joker around to see countless properties can be an expensive gamble if they don't actually follow through.