The owner is not a professional landlord and the property is mismanaged and getting destroyed by the tenant...

I've done ground up development and building, redevelopment, fix/flip, private lending, non performing note workouts, buy/hold rentals, raw land speculating, and probably more if I really thought about all the deals I've done.  

I need some advice and some instruction on the proper procedure in writing up a contract with a private investor and contractor.  

You never know what information your tenant is telling prospects and if what they say does not line up EXACTLY with what you advertise you immediately lose credibility.You really need, at a minimum, a professional leasing agent to show the home when the current tenants are not home.  

I am new to working with private lenders. 

I have been a Commercial Real Estate Broker for the last eight years negotiating privately leased space for various State agencies in California which is a pretty good gig.

We are renting a house from a private party.

Please private message me for any recommendation commercial snow removal contractors

This is a professional forum.  

I don't believe either is very accurate for a real estate professional.