This paper proposes enhancements to the use case technique for eliciting and specifying requirements for embedded systems. The work resulted from the employment of the use case technique for the requirements elicitation and specification of embedded systems in an industrial context. The use case technique is currently considered the state-of-the-art for handling requirements, because of the many benefits it provides. In spite of that, it still lacks proper definitions of the technique's constructs, and a well-defined process for practically applying the technique for requirements elicitation and specification. These are among the major issues that make the technique not readily suitable for employment for requirements elicitation and specification of embedded systems. This paper attempts to fill in this gap. The paper especially reports practical experience with a real-life case study from the avionics industry. It discusses the practical problems that were encountered and provides solutions.