How to plan a lesson

There are many ways to plan a lesson.

You could plan it in the order you're going to teach it.  You could start by planning the warmer and work your way to the end.

Or, you could start with the cheese and work your way back to the entrance of the maze.  Being, in other words, with the final task.  This way you know where you're going.

Or you could go back and forth between the different stages of your lesson.

In EFL, you could start with the grammar and find a topic to match, or start with a topic and add the language you want to teach. 
You could start with a text or a picture. 
You could start from the course book and see how to make it communicative, or start with a communicative task and see how you can make it fit the course book.

No matter how you plan the lesson, always remember:
In the end, you don't teach the lesson...YOU TEACH THE STUDENTS.