The purpose of this study was defining the effectiveness of an achievement making method, a motivating instructional one to improve English learning as a second language (L2). For doing so a case study research design selected and after considering the English scores of students of a language institute and in a purposive sampling method, the subject who was interested in our study has been selected. The scores average for the subject (case) was 71.35 (C) in a 100 points scale. The case, replied to an author made, Persian questionnaire on his English learning experience, as a motivational factor. The case was an Iranian student, 22 years old, male and graduate in industrial management (B.S). He entered in the treatment (instruction) process after passing 8 course sessions (1month).Regarding the results of the subject's first survey on his learning experience ,an instructional method designed ,based on multiple short exams and immediate feedback and reinforcement to modify the learner's L2 experience in a step by step achievement making approach. A general exam on language main skills accomplished after each 4-course sessions alongside replying to learning L2 experience questionnaire. The final results of qualitative analysis of totally 12 months, 96 course sessions and 22 general exams showed a clear improvement in subject's L2 scores (L2 achievement) and also in L2 learning experience. Based on our finding, it can be concluded that, designed achievement making instructional method has been effective to improve subject's learning L2 experience and hence the L2 achievement.