This study explores the impact of rhetorical strategies on the writing techniques of pre-service teachers. It specifically examines how process-based writing instruction, rooted in Systemic Functional Linguistics (SFL), enhances the ability of student teachers to employ effective writing methods in crafting argumentative essays. Utilizing a sample of 98 student teachers from Greece, the research was conducted through a performance-based essay task, supported by two think-aloud protocols. This approach allowed for a detailed examination of the writing techniques used by pre-service teachers, both before and after receiving process-based writing instruction. The study focuses on the application and improvement of writing methods through the use of a rhetorical process approach. The results highlight the significance of rhetorical strategies, such as idea generation and rewriting, in the development of effective writing skills. The study reveals a clear improvement in the ability of students to choose and integrate relevant ideas into their essays after mastering these techniques. Additionally, the findings suggest the frequent use of translation strategies from native to foreign languages in concluding an article. This research underscores the importance of teaching rhetorical strategies in pre-service teacher training programs. By focusing on these techniques, educators can better equip student teachers with the skills necessary to become proficient writers, capable of addressing various audiences effectively. The study advocates for a greater emphasis on process-based instruction to enhance writing competencies in educational settings.