I see this question pop up pretty often. There are a lot of right answers because a lot of different sounds, sequences and techniques work sometimes. I am yet to find anything that works every time but I think it helps to get a little experience and do a little research on what coyotes are up to at different times of the year.
If I were to suggest a general calling sequence that could be used across many situations I'd say:
-Start off with a low volume prey distress sound (rabbit, rodent, or bird) and run it for 2-5 minutes
-silence for 1-2 minutes
-Louder distress sound for 3-5 minutes
-silence for 1-2 minutes
-Howl at loud volume 2-3 times.
-silence for 1-2 minutes
-Change to a different distress sound at high volume and run it for 5-7 minutes
-silence for 1-2 minutes
-Howl several times
-Silence for 1-2 minutes
-Ki-yi or coyote pup distress for 3-5 minutes.
I like to sit on stand for about 30 minutes. If you get a response in the distance but they won't come in, back out quietly and circle around closer to their location and try again. I've found that often a coyote that is a ways off will answer a howl but not come in until you set up close to them. Of course you'd better be discreet when sneaking around after you've called or you'll get busted. I hunt out west in wide open country, rolling hills with sagebrush mostly.