Hello! Firstly I would like to ask you of our location. I am in China teaching various different students in two institutions. One requires English business language skills and the other requires English language skills to Software Engineers. I suspect this may be helpful (I am sure you will get help from others) and would be happy to inform you of our structures.
In any case, when planning, a good idea would be to use a core textbook that will include the skills required from your students and to work around the structure therein. Also, in places like universities you may find that some classes may be of different disciplines, working in different weeks...