The most important thing I've found with my coyote hunting is to ALWAYS watch downwind, and setup where you have visibility downwind. Howls are my go-to method since most people shy away from using them, and I'm quite successful with them this time of year. Any responses that consist of barks followed by a howl are bad, basically the coyote is saying he's already busted you!
Using magpie and crow sounds is good this time of year also and especially with this cold weather, since the yotes are looking for a freebie meal.