Invisibility requires silence. I'm still amazed at how much noise many so-called expert hunters make, beginning at the truck. I routinely have to remind my hunting partners not to slam car doors or tailgates. Noises like that put any coyote within hearing on guard. To separate vehicle noise from the calling setup, put some distance between you and your vehicle before calling. I often walk a half-mile or farther before starting a setup. A properly cloaked entrance requires a conscientious approach to hiding your form, scent and noise. Control those variables and you'll be a step ahead of a tough coyote.
STAY LONGER
Finally, don't believe everything you read or see on television. Most experts and books religiously stress that a coyote setup should last no more than 15 minutes. Regardless if I'm howling or using prey-in-distress calls, I always stay on stand for at least 30 minutes. In fact, I've killed as many coyotes at the 30-minute mark as at the five-minute mark. One coyote-hunting buddy of mine started following my advice and is himself an evangelist for the tactic now, bragging about how many more coyotes he's shooting simply by staying put longer. You'll kill more coyotes if you do the same.
Take your time. A coyote doesn't live its life by checking schedules in its BlackBerry. If you ever get a chance to watch coyotes in open country, you'll discover they often come from a half-mile or farther away. Seldom do they run in; most walk or trot, and they'll often stop and just stare, scrutinizing the landscape for signs of the normal and markers of the dangerous. I learned this lesson the hard way after getting up to leave and repeatedly bumping coyotes that were still on their way to my calls.
Remember: Older, call-shy coyotes don't hurry to approach a calling site. Use your binoculars to scan edges, and to watch for coyotes to appear during the last minutes of light. Be patient and follow the rules set out here, and you'll be rewarded with more fur at season's end.