Just start googling Tiny Homes, Granny Flats, Casitas, "COTTAGES" and/or Accessory Dwelling Units aka ADU's.

Maybe bring a bit of furniture & accessories from your own house to stage it (or rent from one of those rent-to -own places, tip from @Brandon Turner on a podcast, I think).  

I'm currently checking with an agent and others on rent prices for similar properties or even the possibility of turning it into an accessory dwelling. 

Even just entering the listings or vacancies might get you very conversant in the local market.Then you could also make some key contacts, learn the process, and maybe even find your first deal (a client may be willing to owner finance a rental, for example).If you are handy, you might try and work with a firm that does apartment turnovers (make ready) or even as a laborer for a remodeling contractor (especially one that does flip work for others or on their own)--to get the full hands on view of how to get apartments ready to rent or flips ready to sell.Maybe the best hands on way to work in the space is to buy your first rental; maybe your first or next home could be a duplex or single family with an accessory apt.Best of Luck.

The money will be to finance my next deal and/or build an accessory dwelling unit in the backyard, which would also be a rental.And if you have any contacts for hard money lenders, I'm interested! 

I looked into this and FHA will allow this, also the new granny flat laws just went into affect for california allowing "accessory dwelling units" on SFR lots sized up to 50% the square footage of the primary residence.  

If it's zoned as a SFH and only has one APN lookup your local laws on 'Accessory Dwelling Units' it's entirely possible the conversion was unpermitted and you'll get in trouble/have to rip out the 2nd unit if any code inspector finds out about it. 

I think it depends on your market if the homes are flying off the market, you can do minimal staging (accessories) and it will still sell.

I have a similar setup, a large 4br home with an accessory or mother in law quarters in the back with a private entrance for both.

Or use a single family with an accessory apartment and make sure the accessory apartment is also done properly and permitted (and maybe put the renter there, not you).....