Designing better kernel ABIs

All of that is good advice, but I think one of the best things you can do when designing a new interface is to simply attempt to eliminate as much ambiguity in the interface as possible.

Are there multiple ways that an argument or field in a struct can be interpreted? Be very specific in how the interface will interpret it. Be specific about what errors will be returned, and under what conditions. All of that makes for a more tidy interface that is less apt to have problems later.