Pushing domains

Hello, hoping to get some helpful advice.
Scenario is a series of sites that I am going to build and then market and sell to an offline client.
My question is there a guide available or helpful advice by anyone reading this as to how best to handle the situation of pushing and or transferring the domain and any other related issues that come up in these scenarios?
Services to use? Advice or notification of domain renewal to buyer,paperwork needed to transact? Anything else the reader of this thread thinks would be helpful regarding this issue and could elaborate on would be greatly appreciated.

There is a guide I’ve put together here that may be of use to you.