Have you tried incorporating videos to your lessons? Ako kasi I believe a complete lesson should make use of all the macro-skills: reading, listening, speaking, writing. If one or two is missing, regardless of the intended learner level, the lesson cannot be considered effective. For intermediate to advanced students (CEFR B1 to C2), I like to have the students read, watch, discuss, and write about current events, pressing issues, or speeches. I use articles and videos from BBC (they have an excellent Learning English program), TIME, NHK World (for Japanese students), TED Talk, and popular TV shows in America and Britain (depending on whether they would like to master American or British English). With higher level learners, there is an emphasis on production, rather than lexical accuracy (correct grammar and such, although that should not be neglected), so the teaching style has to be more inductive and task-based. You should also bear in mind that each learner is unique and you must tailor your lessons based on THEIR specifications, not yours, so you have to ask at the very beginning what their language goals are, and what they are studying English for (e.g. corporate advancement, migration, etc.) For Business English, I have textbooks by Macmillan English and Pearson ELT, as well as non-ESL books on improving business communication.