I don't hunt Colorado - but I do hunt coyotes!

Great way to get out in the hills off-season, and I figure every coyote zapped is another fawn with a better chance of growing to maturity. I generally use my deer rifle too, a .25-06, just more time afield with that particular rifle...
Camouflage is important. The coyotes seem to be able to see pretty well.
I like a mouth call, dying rabbit, but the electronic jobs are probably better. If they've been called and shot at a lot, they're wary. Consider taking along a feather or something, and a length of fishing line... You can hang the feather where it will catch the breeze and move about a bit while you're calling. The coyote may be distracted by the feather/movement and not pick up on you as readily.
Don't spend too long in any one stand. If nothing happens in 20 minutes, get out of there. Move a half mile or a mile and try again.
Howlers work sometimes. This can bring in big daddy, ready for a fight with an intruder in his territory.
The young pups will be out soon, if they're not already. In early and mid summer they are pretty ignorant and pretty easy to take. After they've lived through a season of people trying to shoot them, and other critters trying to eat them, they get pretty good at survival...
Best of luck to ya! Coyote hunting is fun.