How to avoid creating difficult-to-DevOps and hard-to-maintain projects

I'm finding so many pitfalls from OIC Projects and looking for ways to avoid them. If you have some guidelines, mind sharing them?

I'm writing my Best Practices for creating OIC projects, however I do not find a good solution or guideline… I can tell you What Not to Do and Why - see below- but struggle to tell you what to do instead or how to avoid them…

Here's what I have so far

Guidelines for creating OIC Projects

Main goal

You want to avoid creating a DevOps nightmare and maintenance doom when designing and implementing your integrations.

Create integrations that are easy to maintain (