Almost no body told us about Root barrier, which are simple digging  about 2-3 into the ground, near your foundation to cut invasive  tree roots. 

We always build less square feet so we can capture the highest price per square foot. you can't control your market economics so building and designing and constructing around them is good. 200 sq ft less might be a huge pool or another amenity.

It sounds simple but lot of work is involved.

If you are referring to residential rents then you have answered your question- "Buying right"But buying right is too simple an answer. 

When I’d reach out, I would simply say something simple like “I'm looking for fixer-upper houses and can buy it off market for an on market price.

KISS - Keep it Simple...The more complex an investment does not make it better.

I asked a simple question.

I'm in a different position in life where cash flow is not as important that equity capture.

Hello Mary, without knowing much more you could structure a simple partnership or hold this property in an LLC which can be divided up as you see fit.

I found that most of recommendations to buy a duplex emphasis on positive cashflow or match with simple 1% rule to start with.