Every CELTA lesson plan requires a main aim (the primary language or skill outcome — “By the end of the lesson, learners will be able to use the present perfect to talk about life experiences”) and often subsidiary aims (supporting skills the lesson also develops, such as pronunciation of a specific sound pattern). A frequent source of lost marks: aims that describe what the teacher will do (“I will teach the present perfect”) rather than what the learner will be able to do by the end. Always write aims from the learner’s perspective and make them observable — could you watch the final activity and tell whether the aim was met?