The scope of the project is everything related to the different routes of the Camino de Santiago: history, heritage, people... and the aim is to improve the content in the Wikimedia projects. So there are many ways to collaborate; here are some ideas:
Articles
Editathons and workshops
Online writing challenges
Multimedia
Poster distributed in hostels encouraging to contribute to Commons
Wiki Takes
Photo contests
Release of images under free license by institutions
Travel guide
Guide of the different routes to Santiago de Compostela