Drive, run, and walk each and every block so that you know each one.

I am looking to buy a multi-family there (couple of blocks west from Damen) and am collecting data to see what fellow investors are doing in that area.  

Baltimore is not for the faint of heart and unless you know someone on the ground that knows the city, I would not invest in it if you don't live near it as its a block by block city, that's why institutions have never invested there for sfh.

You might be able to bring the price of the whole block up by getting rid of an eyesore and having 2 freshly rehabbed homes right next to each other.

For less than $600 total, we are installing a  cadet wall heater in each of the two bedrooms.We are a little nervous about two things: 1) How did you pick a place in the room where they are unlikely to be blocked by furniture. 2) We live in a city that doesn't really have winter.

But it literally changes block by block in Baltimore.

For the fish that do bite expect Trailer Park full of sex offenders with pit bulls sitting next to the car on blocks, adjacent to the failing Lagoon.In most cases you're just going to anger people by giving them a letter with a good price to find out they fit the scenario above and you're overpaying, or anger them because you're way under and they won't even contact you.This is why people don't do it.  

As for hot spots, Baltimore is block to block.

Then spend money on amenities and make your block of houses the best block of houses in your area. 

I would go old school and just cover a block at a time.