Motor-skill training is an imperative element contributing to overall sport performance. In order to help coaches, athletes and practitioners to capture the characteristics of motor skills, sport scientists have divided motor skills into different categories, such as open versus closed, serial or discrete, outcome- or process-oriented, and muscular- or cognitive-oriented motor skills. However, in the current sports arena, coaches, athletes and practitioners rarely know of the existence of motor-skill classifications and their implications for motor-skill training. Thus, the purpose of this article is threefold: (1) to introduce the characteristics of open motor skills, (2) to explain the key principles of open motor-skill training, and (3) to describe the general principles of motor-skill training approaches for helping athletes achieve optimal performance. Because many sport skills fall into the open motor-skill category, if coaches can have a thorough understanding of the nature and characteristics of open skills, they can capture the key principles of motor-skill training to maximize athletes' performance in competition.