My two cents
A service blueprint can be used to summarise how a service works, where it works well and where there are challenges. In short, here the steps to follow:
Gather data about what works well and what doesn’t
Display the data in the blueprint
Color code the data to create a sort of heat map
To do so you obviously first need to do some research and gather relevant pieces of information that you can show in the service blueprint.
For example, in the research phase, you could gather:
Emotional level
Pain points
Happy points
NPS and other satisfaction or experience level metrics
Once you have all these pieces of information, you can put them in your service blueprint next to the relevant stage of the blueprint or next to the relevant touchpoints.
Now you can do some colour coding to create a sort of heat map. For example, all the negative elements could be colour-coded in red (pain points, low satisfaction scores), and positive elements (happy points, good satisfaction metrics) could be in green. Pro tip: remember to write legends.
Now, if you look at your service blueprint from a Bird's Eye view, you quickly notice where there are zones with lots of red where you should focus your attention first.