I usually don't have to look very far to find good examples of API evangelism in the field, because the best technology providers are usually pretty consistent and vocal about their practices--allowing me to just pluck from my feeds, and rework as a story for my API provider readership. One of the consistent sources for me out there is from the Docker community, and from what they like to call Docker Captains.
One of the things I see regularly from this Docker community leadership is the sharing of their platform tips and tricks and in-person and online meetups. This is definitely something I recommend other API providers do when possible, but I would also recommend working to integrate the concept into your regular evangelism activities like blogging, weekly newsletter, and Tweeting.
Maybe it is something you could also open up to the rest of the community. Allowing your trusted partners, and your favorite developers to share what their tips & tricks are around API integration and usage are. The idea of tips and tricks is a pretty basic thing, but if you are working to stay creative in producing content, while also keeping things in the realm of actually helping your API developers be successful--it is one that can go a long way each week at meetups, on your blog, newsletter, Twitter, and across all the other channels you are already using to reach developers.
