The nature of work is evolving at breakneck speed. A raft of collaboration tools makes it easier for dispersed groups to achieve common goals, and changing norms regarding flexibility are challenging the conception that an organization’s work takes place in a central location between 9 a.m. and 5 p.m. To cope, and better yet, to flourish in a 21st-century work environment, here are five rules to consider as you seek to optimize your career.