Structuring Seller Finance

[Dane Kania]

Hello,

I have been building a relationship with my neighboring duplex owner. I bought my duplex last year as a house hack and am looking to acquire a new investment soon. It was brought to my attention that she may want to part ways with her duplex for own personal reasons. She is willing to do a seller finance on the property and is open to ideas. Obviously, both parties need to win in this situation. My duplex was bought about a year ago and only needed a few grand in repairs. Hers on the other hand needs a bit more attention.  I have never done a seller finance deal and am looking on input of how to structure it. What are some best practices you all have experienced when negotiating these terms? 

A few details:

-Both her and I's duplex are identical. 

-Mine yields $2500 a month in rental income. 

-Her mortgage is $1,000 a month

-I bought mine for $325,000. (Mostly renovated) Hers would probably cost around $15,000- $20,000 to get it up to par with mine. 

-I am a realtor and bought mine FHA 3.5% down (used 3% commission into down payment)

Any ideas or strategies are highly appreciated!