I search schooldigger.com, (schools = value), city data to learn the median home price & income; check vacancy rates, landlord tenant laws then find a quality property manager if you are keeping buy and holds. Start with the end in mind and work your way backward. Just like flipping. You get the ARV then subtract repair cost, then profit margin to determine your purchase price. You are working your way backward. Learning a market you don't know is just like that. When I 1031'd my CA profits out east I studied on realtor.com (been almost 10 years so maybe better resources now) to find areas that were low priced with high rents and low vacancy rates. Make sure there is a good employment base around the area. Then study the neighborhoods to see if they are mostly investor owned. Stay clear of those. You want to be in a limited investor area (otherwise too much competition when you have a vacancy) and owner occupied neighborhoods tend to take better care of their properties and see higher appreciation.
Just my opinions but that's what I did when investing out of state. Your property manager is key. If you don't like them change, and do it quickly! Don't sign with anyone that has termination penalties or that doesn't list your property on the mls.