This is what's working for us:

  - Branch off master to make your fix/feature. Prefix branch name with "fix/" or "feature/" accordingly. We occasionally use a "script/" or "migration/" prefix too.
  - Do work. Use "git app -p" so commits are fairly small.
  - Make GH PR into master, get code reviewed. CI test are run automatically.
  - Deploy branch to staging environment and test.
  - Merge with GH, deploy to production.

Notes:

  - master is always in sync with production, and so is always deployable.
  - never commit to master.
  - we don't use a develop branch.