The evocative nature of the topic, innovative ideas, novel data sets, interesting presentation, excellent writing style, and positive policy prescriptions all contribute to the quality of an academic paper, which should lead to a positive impression.
All parts of a paper, starting from the topical subject matter, as encapsulated in the descriptive title, motivation, literature review, methodology, modelling approach, data, descriptive statistics, empirical evaluation, limitations of the research strategy, and future research directions, contribute to a favourable impression of an academic paper.