We don't have any Prefect-specific best practices recipes for that. The same best practices apply as you would implement it in Python. For Prefect, the recommendations might be: securely store credentials e.g. using Secrets, separate environments by tenants or in 2.0 workspaces
We may add some recommendations recipes in 2.0 at some point, curious what are you looking for in such a guide? how to move from dev to prod?