Male Form 2,English Tuition recommendation

My child just completed Form 1 in HKSAR. He is not so interested in English but has paid efforts to memorize the vocabularies and study Grammar as required for exams. There has been improvement which however is a bit too slow. The performance is also not steady. For example, in a recent exam, the score in Writing suddenly falls below the passing rate. I want him to become interested in learning English and also willing to try more effective methods of memorizing vocabularies after the tutoring session