Hunter, here's a few ideas and some lessons I've picked up yote hunting over the years. I find that I'm most productive between 10 am and 1pm, if the yotes didn't make a kill during the night or find a meal they'll be looking till late in the morning. This is really a good time if there are any pups in the pack. Dusk seems to be the next productive. When I'm getting ready to hunt a new area I'll take a couple of days to look at areas the yotes may be feeding at, overgrown pastures, creek beds, chicken pens and houses, feed pens, birthing areas for sheep and goats, family dumps on farms, or gut piles and carcases left from hunters or old kills.
As for calls I try to use whats local, jack rabbit, cotton tail, quail peep or whistle, fawn bleep, or even a mouse peep. I also use a tallyho for yips and barks. One other I like is a good howler, just before the sun starts its setting track I'll mimic a lone male. Alot of the time the pack will want to see who the intruder is on their hunting area. I generally call for two to three minutes and wait. If the pack howls back I'll do a couple of yips and another howl to set them off. If I'm using a rabbit or other small game call I'll use it for two or three minutes and repeat after 4 or five. Wait 10 to 12 then repeat it. I've had coyotes show up in the delay time and spook when I made a second set of calls. Watching for ANY movement is critical.
Blending in to the area is a must, and you should have a decent background to break up your outline. I try to call into the wind or across it. A coyote thats unsure of the call will try to circle around you to get a scent of whats there. One trick I found is to take a piece of fur about 10 inches long and three inches wide. I tie on end to the bottom wire on a barbwire fence and let the wind "kick" it around. Maybe the yotes think its hung up, I'm not sure but they will come in on it quicker than just a call by itself.
I don't use attractants like guts or meat. I do use a scent blocker or scatter horse or cow manure around where I set up to help cover my scent.
As for the caliber of rifle, I think thats a personal choice. I like the 223 and the 204, both work nicely on varmits. On a personal note a 416 Rigby will reverse a coyotes direction of travel...FYI. Hope these give you some ideas to work with, good luck and good hunting.