It's easy to get caught up in the cool and grandiose when designing a user interface, but any developer can tell you the real work is in the simple stuff. Take Yes/No or OK/Cancel buttons in a dialog box: what order should they be in? Got the answer? It's wrong.
Google Glass -- glasses with a built-in screen, Internet connectivity and the ability to run apps -- has attracted lots of attention from developers since its launch last year. But how can you build apps for the platform that are actually useful, not just oddities that will disturb passers-by?