You want the Service Design Principles that you write to help you improve the lives of the people you serve. We don't want these principles to be philosophical like "be empathic", where you then ask yourself after reading: "Great, but how the fuck do I do that?"
Therefore your Service Design Principles should be actionable, but at the same time, not limited to only one particular context.
Here are two things you can try to find this right level of depth:
Zoom out, just a tiny bit: don't make it too general as it will lose the actionable feeling, but make it applicable in other contexts.
Ask yourself "will this helpful to me in the future": you are writing to remember a tip, an improvement.