For appealing appraisal, the easiest way is absurd adjustments (and adjustments are often absurd: $10k for a BR when simple query of average 2br vs 3br sold will show value of that extra BR on average, same for bathrooms, etc).  

Which is why I was surprised to receive this response: "That would be a good question for your CPA" when I asked a simple question this tax season.

Tried a simple Google search but was surprised at how thin the options seemed to be.

I also recommend building some simple marketing materials.

(Note: Advertising can be word-of-mouth advertising or something as simple as a “FOR RENT” sign with a contact number posted on the property.

There's not really enough information to understand exactly what you're working toward, but here are a few examples of how you could structure a BRRR with a private lender.It could be an equity split with preferrential payment/buyout, a simple interest monthly payment until refinance, a long term partnership or a hybrid of some of these. 

It's also a simple solution, there are new sub-metering systems available for a few hundred bucks.

While it may seem daunting to identify what one should be doing, it is actually quite simple.

Create a simple spreadsheet or written list to compare the features of each and identify the ones that align with your requirements.

A simple barrel septic system I put in myself.