For what it’s worth - my 0.02 is to do a lot of networking - ask people what they do or have done, find mentors and partners, and start that way.

Knocking on doors I assume and asking residence?

I think you can find a house with a garage apartment in several parts of the city, but i wouldnt say thats a true multi familyfor better cap rates on SFR look to places like missouri city stafford for homes that will have a retail end userfor flips and flood risk properties look more at  northwest houston north of i10best of luck

I am wanting to build and Garage with an apartment above it at my home in Ypsilanti, MI. 

Additions, on old multifamilyWe're buying a property that is in an R3 zoned space and it's advertised as 5 units but it appears like some are converted garage or converted patio or something like that. 

He has filled the garage with a huge safe, racks of tools & power tools, table saw, etc.

Without a basement door everything is up and down steps thru the house .     

I have gotten to know my landlord pretty well and he has been in REI for over 30 years and has 70 doors so I'm guessing he went with that make for a reason. 

Don't wait till you've got that many doors to start operating them that way.

Your per door profit varies a lot...I personally don't want to see less than $200/door on my multifamily deals, and that is considering 10 or greater doors.