Great question.
Here are a few basics to get in place when planning to launch the eNPS surveys/program ->
1. What are the key focus areas you want to get survey results from? Eg, might be work, organisation etc. Do NOT ask templatized questions for the sake of surveys.
2. Break these focus areas down into questions for each focus area
3. Launch the survey
4. Analyze the survey results over time and slice it for your various businesses, goes, managers etc.
5. It gives great insights into where the problems are and how they are moving over time
6. Read all the comments. If not possible, run a sentiment analysis on these comments. A lot of great actionables come out from the verbatims.
Here is an actual sample of Focus area scores over time