Recently I had the privilege and good fortune to present at the 2019 Sitecore Symposium in Orlando, Florida. Below are links to the slides and notes from my presentation on customising Sitecore Marketing Automation plans.
Slides
Code
Github repository containing sample code, utilities and content package: https://github.com/parrya/ma-demo
Troubleshooting and debugging tips
See this blog post for some tips on creating custom activity types in Sitecore Marketing Automation plans.
Resources
Sitecore docs:
https://doc.sitecore.com/developers/92/sitecore-experience-platform/en/activity-types.html
Custom Activity Types in 9.0.x:
https://www.brimit.com/blog/sitecore-9-custom-marketing-automation-action
Automation deep dive:
https://www.linkedin.com/pulse/how-sitecore-9-marketing-automation-works-deep-dive-emmerzaal/
Marketing Automation Achitecture:
https://www.youtube.com/watch?v=0HxUph2YLZc&list=PL1jJVFm_lGnyicywCcwcWa8RtsoiJEbC9&index=5