Be prepared to sit at least 45-60 minutes on each set if you are after a Bob. They will not come in fast like a yote. Use your eyes and binos a lot. Movement helps as well, a feather hung in a bush will catch their eye.
I attended a calling seminar a year ago, and Browtines suggestion is really close to what I learned. I've trapped bobcats for years, along with other nest robbers. Use the feather in a bush technique over my traps. A cat doesn't have a very good sense of smell, and is primarily a sight hunter.
What I learned in the seminar from a guy that travels the country, and produces video's that sell everywhere: Call softly at first, bringing up the volume slowly on suceeding repeats.
Don't use a decoy. Look, Look, Look for a cat sitting on its haunches looking over the area your trying to get them into. He had video clip after video clip of cats just sitting at the edge of the woods watching, but not advancing. He said the best time to get them is when you get tired of calling and get up to go home. The movement in the corner of your eye will be the cat hauling butt!
My friend Scott Ruff will be putting on another FREE seminar at Bass Pro in Broken Arrow on Jan 24 at 7pm in the upstairs seminar room if your interested. Tell him I sent you, if you attend.