Look for Metropolitan Statistical Areas (MSA's) that have growing populations, growing jobs, modern/diverse economies where businesses are investing capital.

A neighborhood can include more than one zip and a zip can be incredibly diverse here in Philly. 

Louis is a large and diverse market.

However, if you're specifically set on one of those markets I'd recommend Kansas City - landlord friendly state, lower property taxes, increasing population and diverse economy, a good supply of potential rentals that product good cash flow with a decent chance of future appreciation.

Some people STR a literal 100 sq ft Native American teepee...doubt you'll find many takers for LTR on that thing.That said, portfolio diversity is important for lots of reasons. 

For me, not feeling safe is a hard pass.Houston is very diverse and large.

Personally, I like to invest in areas with diverse economies.

The beaches, the weather and and the diversity of people and ideas makes this an amazing place.

I'm wanting to start investing in real estate at the first of the year, and I have a few questions.I live 15 mins from the DFW area in Texas.I'm mainly wanting to focus on 1-4 unit rentals, but I am considering other things to speed up the process and to also have  diversity.

Tampa is a comeback city...Water Street Tampa is one of the largest redevelopment projects that Tampa has seen in recent history, and it’s helping transform the city into a vibrant, diverse and attractive option for young people.