@Bryan Schwartz a lot of trial and error - and even then, you have to watch them as they get greedy when you aren't looking.Try going to Home Depot Saturday 6am - those are the hard-working guys!

The next step I see is to buy a (ideally) quadruplex to househack.Please excuse my rookie questions.

Tenants save money when using a shared meter, so there's plenty of room for error when calculating how to distribute the charges.

You could read 100 books and still need to learn more because certain things must be learned through trial and error.

@Greg Schreffler as a tax professional, I have seen returns from TurboTax that have many errors on them.

Record lease data using software or spreadsheets, correcting any errors or discrepancies.   

It sounds like you're in a bit of a tough spot, but here are a few options to consider: Go through the full report in detail to identify any errors, discrepancies, or inaccuracies in the comparable used.

They were not straight forward with the renovations and even tried to hide a painting error they made and have us pay to have the room redone.

I can't vouch for it, but the hosts of the Rookie podcast wrote a book about partnerships that may be worth reading before you take on a partner: https://www.amazon.com/Real-Estate-Partnerships-Acquire-Achi...

Then telling folks you're a rookie?