Most of the students who come to us for English speak it perfectly well and write it badly, which is a specific problem and not a general one.
We teach the mechanics that nobody has time for in a class of thirty: sentence structure, tense agreement, paragraphing, punctuation that changes meaning, and the difference between how people speak here and what an examiner expects to read. Then comprehension, which is mostly a reading skill rather than an English skill, and writing under time.
Every piece of written work is marked in full and returned with corrections the student has to make. Marking a script and handing back a number teaches nothing; the rewriting is where the learning is, and we make time for it in the session.
Reading matters more than anything else we can do in two hours a week. We lend books, we expect twenty minutes a night, and we ask about them.
Six hundred rufiyaa a month, two sessions a week, groups of eight.