How do I know I'm analyzing a property properly

[Munira Hassan]

I found a nice duplex with small issues (water heater needs replacing) other then that it's pretty much ready to rent. I'm paying by conventional loan with very little money down ($1000). The Duplex is $105,000 with a single car garage and additional parking. 2 bed and 1 bath first unit. 1 bed 1 bath with potential bedroom second unit. New roofing and renovated bathroom in second unit. My loan requires me to be own occupant so I'm planning on living in the smaller unit since I'm single and renting out the bigger unit for a family (bigger unit has it's own dinning space hardwood floor throughout the house). My question is since I did the analysis how do I know I'm doing it correct. I've watch the video on it and read the blogs about rent analysis. But I still feel nervous. This blog here about how to own your first duplex shows you how a potential looking duplex once analyzed can be a disaster.  http://www.biggerpockets.com/renewsblog/2014/07/19... . I just wish I had help knowing I'm analyzing my potential correctly. I can think I'm doing it right when really I'm missing an important issue. 

Thanks for your help in advance.