There has been lots of stuff that I've found not so helpful on the Celta Course, but one thing I've liked is the focus on how to plan a lesson.
For grammar lessons (I'm teaching the Simple Past on Thursday), there are a few points to consider:
1. Context. If you give no context, students won't care what you have to say, or remember it.
2. Meaning. What is the grammar point used for specifically.
3. Forms. Including negatives and questions. Many teachers forget these last 2 points.
5. Practice. Controlled and Free.
I have to admit, I've been a little weak on context in many of my previous grammar lessons and didn't really say much about pronunciation. If I take only one thing from the course, this will be it!