Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
Information Architects are the Architects of Understanding. They “help users to understand where they are, what they’ve found, what to expect, and what’s around.”
Information Architecture
Information Architecture (4 Parts) — UX Knowledge Base Sketches
Knowledge
Domain Expert Interview — UX Knowledge Base Sketches
Domain Experts / Subject Matter Experts / Industry Experts have invaluable knowledge that you can (and should) apply during your UX process. Domain expert involvement is not an alternative to UX research, and a domain expert is certainly neither a “user expert” nor a designer.
Interviews
Domain Expert Interview — UX Knowledge Base Sketches