I make my own coyote calls from mesquite, and a piece of plastic from a milk jug. Been killing yotes with my own calls for a very long time. I also use various other calls, most hand made as well. Changing things up can fool even the most educated coyote. I start with the typical dying rabbit type, and then progress through various types, including a turkey call, which I make from various different materials, quail call, crow call, hawk, you name it. A couple blades of sweet grass or other hollow type of vegetation is very good for imitating turkey, quail, and even a dying rabbit, and can be used with little or no work needed to fashion it in the field.
Different predators and scavengers will draw them in. When they hear a scavenger like crows and vultures, they know something is dead or dying and will show up for an easy meal. Same with owls, hawks, or any other typical predator, it signals something is dead or dying. Just by switching things up alone can be very effective at getting them to come in and investigate.
I also like to hang a couple feathers in a bush. It adds to their curiosity when they get within range to see them moving around in the breeze. I also snag a couple drops of my wife's skunk scent she harvests from skunks that she uses for trapping, I put it on the feathers and around the general area, I think it helps in covering my human scent.
GS