Advantages: highly memorable, motivating, good starting point for a culture-oriented lesson, helpful in memorizing target structures and vocabulary, incidental vocabulary learning
Keeping it secret: don't give away the song choice, take into account students' age, time of day, language proficiency level, musical interests, prepare various activities that illustrate the teaching focus
Introduction: pre-listening questions that set the scene, provide visuals
What's the story + vocabulary/grammar practice: teacher chooses words from the song to make up a story, use illustrations to clarify vocabulary, choose only one grammar structure/tense/phrase to practise
Reveal not all: students use vocabulary, grammar structure, have a feel for the story, fill in the lyrics with the target language
Surprise! Surprise!: students listen to the song, check the lyrics (gap filling, misused words, mixed up words, paraphrasing), teacher provides additional information on the song, performer, historical facts