Which components might be included in a lesson plan?

A lesson plan may include the development or outline of the lesson, the varied materials and media, and the specific objectives, so all of these belong.

The development or outline lays out the sequence of steps the teacher will follow.

Varied materials and media supplement and clarify the content for different learners.

Specific objectives state, in measurable terms, what students should be able to do after the lesson.

Leaving out any one of these would make the plan incomplete, and all the listed elements are needed together.

The classic five step lesson plan of preparation, presentation, association, generalisation and application comes from Herbart.