That's a hard question. I've done some of it, but mostly with elderly people (I have led a U3A Latin group for four years). My first problem is always in deciding how seriously they want to learn. If they have 'done' Latin to some level in earlier years, I begin by offering them a couple of easy, short texts on a subject that they will recognize, which either makes them give the idea up immediately, or raises their enthusiasm — there never seems to be any havering: always one result or the other. It's no problem then for the real enthusiasts, whom I ask to buy a Kennedy for reference while I develop the syntax as fast as they can respond. I think that any textbook, within reason, would do in such circumstances. If they have had no Latin at all, I begin by talking about the grammar of the languages that they do have. If they once have enough grasp of accidence systems, it becomes quite easy to lead them up to Latin before continuing as with those having some previous experience. If you would like to go into this a bit further, why not send me a PM?