I have one rental property and have had good luck with it. I also feel bad that everyone is piling on poor catastrophe for not already being a property baron, so AMA!
My tips:
-Buy a house (preferably with multiple units) right before property values and rents skyrocket. That's my #1 tip.
-Living close to the house is a good idea. Can walk over to fix piddly stuff.
-Having a property manager usually doesn't make sense if you're just renting out one unit.
-Do everything online--Paypal/Venmo rent, Google Doc lease, Google Form application, post on Zillow/Craigslist/etc. Makes life way easier, especially when tenants turn over.
-Always always always contact the previous landlord before renting to someone. Ask a few simple questions (are they clean? do they pay rent on time? would you rent to them again?) and you should learn everything you need to know.
-If you don't have a kid to mow the lawn, write into the lease that they need to mow the lawn.
-Be a good landlord. Always give 24 hours notice before you go over. Fix stuff (or better yet--pay to get stuff fixed) quickly. Then give your tenants a referral bonus if they find your next tenant.
-Hire someone to do your taxes.