In no particular order, off the top of my head: landlord -
friendly laws, no rent control, population trends, total population in the metro (I won't invest in super small metro areas /
towns), unemployment rate trends, vacancy rate trends, income trends, rent trends, economic trends for the metro, weather (as it pertains to potential expenses - i.e., I don't have to worry about clearing snow from a parking lot in Scottsdale AZ), purchase price, expected ROI, how fast you can evict, insurance rates, and property
taxes.