I hunt the intermountain west, not Texas, so maybe things are different but what I have noticed is that:
Bobcats are much harder to call in the north vs Texas. I have no idea why but many serious callers here go years between seeing bobcats, where in Texas they seem to respond to calls "relatively" often. There's plenty of cats here, BTW, but maybe Texas is absolutely over run with them. I dunno.
Bobcats like bird sounds. I have got them in with a rabbit distress, but most I have called came to some sort of a bird distress call.
Bobcats seem to loose interest easy and have a short attention span. Continious calling is better than the normal coyote sequences of call, wait, call, wait, etc. This is where an electronic call is nice.
Decoys help. Even a turkey tail feather tied to a string blowing in the breeze helps. Anything to keep their attention.
Others are right that they come in slowly...stalking and using cover unlike coyotes or fox who often run in to the call. If I suspect a bobcat is in the area or if the country has that look, I will call for a full hour. It has paid off.
