For coyotes, watch coyote hunting videos to learn how to call. Get a good open reed type call, they are the most versatile.
You don't need to spend hundreds on an electronic caller.
Skunk essences are the best cover scent.
Don't over use your call. About half my coyotes I ambushed without calling.
Learn where they go and what they do. They like to use game trails, cattle trails and other paths. They will hug fences and other structures as they travel.
They like to poop on top of things to mark territory. Even trash dumpsters.
When you are about to quit, they show up.