Pervasive games have been proposed as a suitable way to support learning, especially in places rich in information, as for example museums and cultural heritage sites. This paper reports on the work performed to identify guidelines that help designers in developing games able to provide an effective learning experience in such contexts. Such guidelines complement other proposals available in the literature. The presented contribution is a first step of a wider work aimed at deepening our understanding of pervasive educational games, with a special emphasis on games in the cultural heritage domain, in order to inform the designers of such challenging applications.