My first rental was as an owner occupant. It was not intentional to become a landlord in the sense that I knew what I was getting into. I bought the house for $122,800. The rent at the time for the upstairs (Boston style duplex) was $630/month, under rented even at that time. I remember the grief I got from the mother of my tenant when we met and I informed the tenant that I was raising the rent to $700 for the up apt. The current rents are now $850 down and $1000 up which meets market standard.
The current market value of the home rests in the $170k range.
My story is more falling into something good and holding on. I've learned a lot over the years and have continued to expand my portfolio as well as set loftier goals. There was no criteria that I was operating with at the time. I really didn't start thinking that way until BP and I grew closer over the last several years. ;-)
The worst thing you can do is nothing.