Several studies have found that mentions of research articles in public media can have substantial effects on the articles' later citation counts and altmetrics. However, little attention so far went into investigating the potential relationship between qualitative properties of press texts that promote research and the research’s impact. In this research in progress, we set out to manually analyze and compare the press releases published on EurekAlert! to promote a sample of 120 research articles, 60 of which later performed remarkably well concerning selected article-level metrics, while the remaining 60 articles later performed comparatively poorly. As a preliminary result, qualitative differences could be found regarding the press releases' structure, linguistic accessibility and the existence of narratives. First applications of our in-development codebook suggest associations between press releases with poor structure or accessibility and promoted research articles' metrics performance. We conclude with indications towards numerous promising paths for continuations of this study.