Not to self-promote, but I wrote a post for someone in your situation here:
http://forum.mrmoneymustache.com/real-estate-and-landlording/evaluating-a-rental-property/It covers a lot of the basics on the specifics of how to evaluate a rental property, as well as some of the conventional wisdom on what objectively makes a property "good."
Finding good property management is equal parts numerical and human skills. My advice would be to interview a number of property managers in the markets you are considering. Then read all of their leases, and all of their property management agreements. Create a spreadsheet with all of their charges, costs, and policies. You'll quickly learn who the outliers are, and what "normal" for that market is.
MsSindy gave you great advice of BiggerPockets-- I said in the thread above and I've said elsewhere, but a great way to network and become familiar with PMs is to see how they behave on BiggerPockets. Often helpful and visible community members on BP who are in the property management business are good ones to consider. Just start reading, and reading, and reading. Try to understand the basics, but eventually you will need to just jump in. Most of what you will learn will be learned by doing.