Background: Little empirical evidence is available in the medical field defining the most important features of a scientific presentation. We sought to empirically identify what features of a scientific oral presentation experienced reviewers focus on when asked to identify the best features and areas to improve. Methods: Observational study of 44 presenters at a scientific meeting over a 4-year period. Reviewers observed presenters and identified the best features and made suggestions for improvement using an open-ended form. We developed a coding form based on three domains: content, slides, and presentation style. Two raters blinded to the presenter then coded the comments, and disagreement was resolved by concurrent review. Results: Reviewers made at least one comment about content in 42 (95.5%) of the presentations, about slides in 38 (86.4%), and about presentation style in 42 (95.5%). The most frequently extracted comments on best features of presentations in the domain "content" were identifying a key concept (43.2% of presentations) and relevance (43.2%). Similarly, best features in the domain regarding "slides" were clarity (50.0% of presentations), graphics (27.3%), and readability of the text and font size (22.7%). Finally, best features in the domain regarding "presentation style" were clarity (59:1% of presentations), pace (52.3%), voice (47.7%), engaging with the audience (43.2%), addressing questions (34.1%), and eye contact (22.7%). Various other comments were noted to improve presentations. Conclusions: Important features during oral presentations relate to specific areas of content, clear slides, and a presentation style that was well paced, engaging, and clear. Nonverbal communication is important in oral presentations.