Health IT evaluation studies have often been found to be of limited quality. To address this problem, several guidelines and frameworks have been developed as tools to support improvement of the quality of evaluation studies. In this contribution, we review available guidelines and then present the Good Evaluation Practice Guideline in Health Informatics (GEP-HI) in more detail. GEP-HI is a comprehensive guideline which supports especially planning and execution of a health IT evaluation study. The GEP-HI guideline helps to overcome the quality problems related to weak study planning and methodological study design. We also discuss application of GEP-HI on an evaluation project and discuss the need to publish systematically following the recognised publication guidelines. Finally we discuss the future trend on multi-method evaluation approaches.