This study was conducted to find out the effectiveness of my writing instruction and prepare for the following writing instruction in a graduate school context in the Southern part of South Korea. To achieve the goal, three research questions were raised and answered in a given order; 1) Participants of the study (N=27) show progress in writing in terms of accuracy and fluency, 2) The most frequently appearing errors appeared in the pretest were Mechanics (Title) > Meaning > Adverb > Article. 3) As to the remaining errors in the posttest, Meaning > Article > Mechanics > Adverb > Sentence types (S+V, and S+V) errors survived at the end of the semester. Instructional intervention was quizzes. Based upon the findings of the study, instructional intervention, including writing, was suggested as the form of the quizzes in the future.