I know that many people propagate plant cuttings in water but I don't use that method because of the possibility of rot. I've been using the rooting hormone powder in my photo below for quite awhile now because it's readily available at Home Depot.
I have heard some people talk about using ground cinnamon, which is supposed to be an anti-fungal and also stimulate root growth but I've never tried that method. I will have to test it out one of these days soon!