There are a lot of great free resources out there on Service Design. Here is a selection of sites where you’ll find them:
The Service Design section of the Swiss Innovation Academy website.
A guide I wrote with links to 40+ resources that will help you to become a service designer.
Practical Service Design: lots of resources on Service Blueprinting
Service Design Tools: a list of methods that are used by Service Designers
Slack communities: on the slack communities of the Service Design Network
and Practical Service Design you’ll find links and resources specific to our practice