I sold my rental property a couple of months ago, and it was a happy, happy day. Some people do ok, but it's a tough road. I tried the professional route, but that really sucked everything out of it money-wise. After that, I did it all myself. Not very difficult really in the day to day activities of running checks on potential renters or taking rent checks.
The big problem is finding someone that won't tear the place up. That's a lot more difficult than it sounds. My last tenants did about $10k worth of damage and it took me over 6 months of my time to fix everything, and that's using every spare moment I wasn't at work. My parents have about 10 rental properties, and everyone is commitment in time and money, even the ones that are paid off. This is not something you want to do casually, it's a definite commitment.
That brings me to things that can and will go wrong, such as the HVAC system, the roof, fencing if it has it, appliances, plumbing, etc., etc. It only takes one major item to set you back a few years in rent profit.
And make sure you have it insured not only for loss such as fire and flood, but also liability should someone get injured. One of my parent's renters burned their place down and then sued because they would pay for their belongings. Before you laugh and say that won't happen, they still had to pay an attorney and go to court. Even though they won, it was a significant cost in addition to the headache of rebuilding at the same time. Then they had the gall to want to rent there again, and threatened another lawsuit when my parents refused.
He had a sterling credit report by the way. That's not always a good indicator.
Their best renter was a stripper by the way.
Other things to keep in mind. At least around here property values are staying even. One of the big pluses of rentals has always been their rising values. Not to say they won't in the future, but for now, no. You also will need to pay income tax on the earnings. A plus is that at least for now, you can deduct all improvements and mortgage interest. They keep rumbling about cutting these back, but for now you can.
Not trying to talk you out of it, but it can be a lot more work than many think.