I know there are gonna be people who are going to say simple trial and error - I am looking for resources on calling in coyotes and other Varmints but mostly coyotes!

Are there certain calls that are better by season, location etc....?

Time of day, baiting vs. not baiting?

If you guys could direct me to any specific resources I would be very appreciative!

You could read for months at predator masters website.
When you start talking about baiting then you are getting away from calling coyotes into ambushing them so whole different aspect.
Just like calling any critter ,turkey,elk,duck,or predator ...it's all about setup. Getting wind,sun position ,visibility and having target animal within hearing along with good camo and staying still will get you a long way.
About any ole sound will work but especially Wabbits

I use a Fox Pro, turn it on and just let it scream. I use the rabbit sound and occasionally the injured pup. For me howling has never worked.
Decoys work, coyote is watching it not you

For set up ,
Wind in your face
Sit in front of a tree or bush so you are not silhouetted .
Sit Really still.
Watch your down range! Houses, cows trucks going by. I use either varmint bullets or frangible bullets to reduce ricochets.
Hunt at sunrise and sunset.
Starting out if you get one coyote a day you are doing good.
Don't give up. One day it will all click and you will be the expert.

Mark

This time of year you should have great success with pup distress call. Always run a rabbit or jack rabbit distress then after a shot switch to pup distress. I start off calling on a low tone, maybe 5 minutes then a 1 minute break, then medium tone for 5 with one minute break followed by loud for 5. If nothing shows after 30 minutes total I move on. Always using a moving decoy, usually a rabbit tail by Primos

Here you go. This is an article I wrote for "Predator Xtreme":

http://www.predatorxtreme-digital.com/200904#&pageSet=37&contentItem=0

Use a suppressed rifle if you have one.

Remember that coyotes learn from your mistakes just as well as you do. If you get busted, leave that spot alone for awhile. About the worst mistake made is associating your known presence with a caller sound. As Bob's article mentioned, getting setup is very important. This is where one gets busted most of the time, and you never know it.