Academic writing is at the centre of teaching in higher education, fulfilling a variety of functions, including asking students to produce paragraphs, essays, or sit written exams. This paper argues that the current writing provision in most departments of English in the Arab world should be viewed as offering more practical support in the writing process. To that end, 100 argumentative essays were collected, from English-writing classes at the Department of English at Al-Zaytoonah University in Jordan, to study the role of the topic sentence and the thesis statement in ensuring paragraph unity, topic unity, and text organisation. A detailed qualitative data analysis was undertaken, supported by quantitative analysis to account for the frequencies of the writing breakdowns. The results showed that most of the students failed to write effective topic sentences or thesis statements that relate directly to the posed question. They also failed to introduce ideas for the subsequent discussion. Additionally, most of them introduced undeniable and broad opening sentences that were globally related to the text; consequently, they failed in sustaining topic unity, paragraph unity, and text organisation. The paper suggests that academic staff should be more involved in practical writing courses to help students handle the specificity of academic writing requirements. It is expected that the study will inspire re-designing the writing syllabuses.