I live in Kalamazoo, MI and I have 2 properties in Chicago that I manage myself. I have found that you need great contacts in or around said properties in order to make it easier to manage. Plumbers, carpenters, electricians, or whatever service you might need when something breaks down, are always needed at a moments notice. I have compiled numerous contacts in these industries, whether by word of mouth or hiring them for a job. Having local, city, township, or state phone numbers handy is always a plus. Including gas, light, sewer companies numbers. Downside to all of this, you will be constantly on the phone and you will have to rely on other people for everything.
Or you could just hire someone to manage your properties for you. I have no experience with management companies, but you can find great info on BP on that topic.
I have found that even though I'm 2.5 hours away from my tenants, as long as there is a systematic way on how you deal with issues, concerns, or whatever may happen, it's actually not that bad. In order to start a system for handling any issues, you need a lease that spells everything out for your tenants so that everyone is on the same page from the start.
I found a relative, that I trust, who is just getting into REI so having him be my middle man has made it much easier. Plus it gave him a intro into REI.
Most importantly having great tenants is key!
Hope this helps!