On a day to day basis, I deal with W3C standards. However, there are certainly sets of standards (or guidelines) outside of the W3C which are good to be aware of. Thanks to Kim Krause Berg, I’m now aware of another document: Research-Based Web Design and Usability Guidelines, courtesy of the United States Government.
One of the keys which makes this worth noting is those two first little words: “Research-Based”. There’s nothing better than research (and user testing) to provide you with a better idea of how your ideas will go together.
From the foreword, by Dr. Ben Shneiderman:
Guidelines should be more than one person’s lightly-considered opinion, but they are not rigid standards that can form the basis of a contract or a lawsuit. Guidelines are not a comprehensive academic theory that has strong predictive value, rather they should be prescriptive, in the sense that they prescribe practice with useful sets of DOs and DON’Ts. Guidelines should be presented with justifications and examples.
Download it, read it, and absorb it.