The study establishes that teaching approaches exert a significant and direct influence on students’ achievement in directed writing among technical secondary school students in Douala, Littoral region. Despite the centrality of directed writing within the English language curriculum, ongoing challenges related to pedagogy, contextual factors, and learner engagement continue to impede student performance. The research systematically identifies the predominant instructional methods employed, critically evaluates their measurable impacts on students’ writing proficiency, assesses the role of teacher feedback, and investigates the manner in which specific contextual factors mediate these effects. Through the application of an integrated theoretical framework, encompassing genre-based theory, task-based language teaching, language process writing theory, communicative competence, and a competency-based approach, the study provides a comprehensive analysis of these interrelationships. Employing a mixed-methods methodology, including classroom observations, analysis of student scripts, and assessment of writing outcomes, the findings illustrate that differentiation in teaching approaches corresponds closely with student achievement across dimensions such as task fulfillment, content development, organization, language use, and mechanics. The consistently low levels of achievement observed across these criteria underline the necessity for educators and policy makers to implement targeted adaptations in instructional practice and curriculum design. The implications of this research are significant: it offers clear, evidence-based recommendations to inform and enhance instructional methodologies, guide curriculum reform initiatives, and reinforce the effective implementation of competency-based approaches within Cameroon’s educational system, thereby contributing to the advancement of writing pedagogy in comparable educational contexts.