EXPLORING THE DEVELOPMENT OF ENGLISH WRITING SKILLS AMONG SUCCESSFUL EFL SENIOR HIGH SCHOOL STUDENTS: A QUALITATIVE CASE STUDY
English writing is considered one of the most difficult skills for English as a Foreign Language (EFL) learners, although some students achieve excellent writing proficiency despite learning in a non-English-speaking environment. This study explored how successful senior high school students developed their English writing skills. Using a qualitative case study design, the research was conducted at SMA Katolik Santo Petrus Kanisius Palangka Raya, Indonesia. The participants consisted of ten purposively selected Grade XI students with strong writing performance and one English teacher as a supporting informant. Data were collected through classroom observations, semi-structured interviews, and document analysis, and analyzed using Braun and Clarke’s thematic analysis. The findings revealed four key practices that supported writing development: planning through brainstorming and outlining, applying multiple learning strategies such as reading, digital resources, and vocabulary building, engaging in regular writing practice with persistence and positive attitudes, and improving writing through self-editing and teacher feedback. These interconnected practices enhanced students’ organization, language accuracy, vocabulary, and overall writing quality. The study highlights that successful writing development results from the integration of cognitive, behavioral, and reflective processes, emphasizing the importance of process-oriented writing instruction in EFL classrooms.