I recently completed a CELTA course and have been applying for jobs. One employer got back to me and I now have a scheduled interview. They ask for a lesson plan to be submitted. As you can guess by the title, it's a one-to-one lesson, the teaching point is grammar (such as going to vs. will) and it has to be 90 minutes.

"90-minute one-to-one lesson that will incorporate one of the following grammar points (please adjust the level accordingly). It is NOT the first lesson with the student"

On my Celta course I have only done 40m lessons, each one having a different teaching point. I'm therefore a bit confused about staging a 90 minute one, and was hoping I can receive some guidance.

As it is not the first time the students have studied the grammar point, you should aim to have them using the language early in the lesson; have them using it in a speaking exercise; the practice part should be longer than the presentation/revision.

The interviewers know that you are new and are not looking for a perfect lesson plan; it just needs to be good enough and show what you learnt on your course.

I know this is too late for the original poster, but here is my tip any-way.

For most minds, including adults', ninety minutes is too long to sit or do mental work in general -- unless there is a break. So, I would build in a break (and a review where the grammar is reviewed in a different, applied way).

Just replying to the question of 90 minutes. Practically all my adult lessons are 90 minutes. For children I have 1 hour lessons. But for adults 90 minutes is ideal. It gives you time to review homework. If it's a grammar lesson it gives you time to explain and practice the grammar point. If you see any fatigue creeping in, get your students to stand up and have some activity which gets them to move. It could simply be thrwing around a ball with questions and answers.