I haven't used SQL Server in a professional context for 5 years but I have used what I have learned from my past life as a SQL Server DBA and from the way the Redgate tools approach things to find ways of facilitating safe experimentation.
Page 16 of the Redgate State of Database DevOps 2018 highlights the areas on which to focus.
Local experimental environments are essential. Scripting the production DB and keeping it under source control is also a corner piece of the puzzle.
Thinking about how you would test a scenario adequately and then designing mechanical test scripts to carry them out. Every meaningful test reduces the risk for the eventual live deployment. What i have found is that the tests find problems I would not have expected and early enough to address while developing. It's uncovered unexpected tech debt.
The important bit is to recognise that every step forward is a step forward. Just because it doesn't answer every question doesn't negate the value of what has been achieved.