Coherence is considered one of the characteristics of effective writing. Topical structure analysis (TSA) has been taught to students as a revision strategy to raise their awareness of importance of textual coherence and helps them clearly understand its concept. This study aimed to investigate the effectiveness of TSA instruction in improving university students' writing quality and to explore the proportions of topical progression in essays written by high and low proficiency students. It also examined the opinions of the students on TSA instruction. The participants consisted of two groups of 20 third year students majoring English Education at Chiangrai Rajabhat University. Data were collected through the pretest and the posttest of essay writing, two selected essays of high and low proficiency students, a questionnaire and an interview. The results indicated that TSA instruction had a significantly positive effect on students' writing quality. More specifically, TSA instruction was more beneficial to the low proficiency students than the high proficiency ones. Further, both successful and less succesful students employed the sequential progression the most in the essays. The students had positive opinions on TSA instruction.