I hate to start yet another new coyote hunter post, but hoping someone can give me a few hints.

I went hunting for coyotes yesterday for the first time; actually it was the first time hunting anything in 17 years. I have a friend that let me hunt on his wheat farm. He tells me every evening he hears the coyote yaps and howls of them. Well I got a little cammo'ed up (don't have much in the way of cammo, pants, cammo boonie hat, and dark green long sleeve shirt) and went out with a portable boom box and some sounds on a cd I got of the net.
Long story short I just sat in the hot 85+ semi dense woods all afternoon and evening and didn't get anything more then a few deer looking at me funny as they cursed by. Bad point didn't see/hear any coyotes, good point I know where I'm going to deer season if I decide to hunt them.

Can anyone give me a few pointers on time of day to hunt them, should I go to the bigger section of woods (15acors instead of a 7acor section), stay near the stream, better cammo?? etc....??? Anything I can try that may work better in the central Ohio area.

Thanks for any help/idea's
Rebel Turtle