In this paper we present the results of a heuristic usability evaluation of three annotation tools (GATE, MMAX2 and UAM Corpus-Tool). We describe typical usability problems from two categories: (1) general problems, which arise from a disregard of established best practices and guidelines for user interface (UI) design, and (2) more specific problems, which are closely related to the domain of linguistic annotation. By discussing the domain-specific problems we hope to raise tool developers’ awareness for potential problem areas. A set of 28 design recommendations, which describe generic solutions for the identified problems, points toward a structured and systematic collection of usability patterns for linguistic annotation tools.