When I am calling with a partner we always set up so that the shooter is anywhere from 50 to 100 yards down wind. Coyotes will most always circle down wind from the caller to check him out.
Also, this time of the year it gets REAL hard to call coyotes in. Two things contribute to this in my opinion. It's late season, and have heard a lot of calls. They're what we call educated, and believe me, some of 'em have PhD's at this point.
The other factor is that they are breeding right now. Most are paired up, and are real hard to bring in 'cause they're busy.
Have you tried making coyote sounds? Howling, barking and yipping are some of the most effective sounds I have in my bag 'o tricks this time of the year. Get you a good open reed call like the Tally Ho and listen to some taped sounds of coyotes. It will help you this time of the year.
Other than that, keep trying and don't get discouraged. They're a lot smarter than people give them credit for.
And remember......If it was easy everybody would be doing it