First, I would love to see the learner's level, and take it from there. Every lesson I would focus on one grammar principle to master at the end of the lesson where the learner can apply it in a conversation. Approaching the grammar principle at the beginning of the lesson, first a demonstration of the principle in use, then learning how to use it and in what situations, and then spoken and written practice is what usually works best! I love art, specially cinema and literature, so I usually base my lessons (depending on the learner's level) on a conversation about a movie, book to create an interesting topic and discussion.