OP,
you have these classes of properties:
A- low headache, high price (long term, low gains, could gain a lot of appreciation) = million-arish hold (yep they still rent, california regular prices not included)
B- middle class (long-term, lesser headaches, some/more appreciation)=you could be living there
C- blue collar (still not for beginners; still need specialized support team) + you need to allow for some loses in your business plan
D- War zone (need REALLY specialized landlords with REALLY specialized support teams
; not for beginners or faint of heart/stomach/liver; you need cajones/huevos of stainless steel and PROTECTION (legal or not)
F- you're in trouble = you're in deep [self censored trouble attribute]!!!
now if you are handy:
- you need them close to you (no more than 60 minutes, preferably under 30 minutes)
- choose them in good/good-ish school districts
- choose them based on local supply... (retirees/young professionals, etc etc)
i suggest the better is to contact the local REIA (Real Estate professional association) or Landlord Association(already recommended) and find out more from the "been-there-done-that" t-shirt crowd.
(already mentioned in the thread):
you are in it for the long term
any quick deals/home-runs = cherry on top.