As in recent years, tablets and smartphones have started their great triumph and are found almost everywhere in daily life, new fields of use are opening up. The frequent usage of these devices awakes the ever-present natural curiosity of children. As the consumer groups of apps are getting younger and younger, there is an increasing number of them tailored to this target group. Especially the niche of learning apps, in which knowledge should be taught during use, is steadily growing. To develop software for children properly, special needs and the development of children should be considered, for example regarding the attention span or the manner of communication. As the developers of apps often have only limited knowledge about these conditions, this thesis will develop guidelines, which provide them with vital information for the optimal implementation of educational apps for children between 4 and 7 years. For this purpose, the target group is analyzed by a systematic literature study and crucial insights will be gained. After creating the guideline set it will be validated by the test of some apps using heuristic walkthrough strategy. In a revision of the guideline catalogue any gaps or incorrect formulations will be detected and eliminated. The result of this thesis represents a comprehensive catalogue of 41 guidelines, which try to draw attention to the particular challenges during the development of apps for preschoolers.