howler gave good advice.
I agree that Randy Andersons videos are a good place to start.
Also go to www.predatormasters.com that is where the callers hang out.
Some of the best callers in the country post there and tons of information is given out daily.

Watch the wind and set up where you can see a coyote if you do call one in.
Use camo including hands and face, sit still and start calling.
It is tough until you have success and build the confidence that it will really work for you.
Good luck.