how fast instruction proceeds
amount of success needed in practice (level of challenge)
what needs to be said to convince learners the topic is important
what will work as attention-getters, and how often to use them
what examples you need to provide, in what frame of reference
the frame of reference provided for practice items, exercises
how much structure will be needed in the instruction
how instruction is organized
what media should used to deliver (teacher, computer, video, text, ???) etc.