first try to get a book on the vehicle, this should about $20 to $30 and a good investment.
Did this just all of a sudden happen or have you noticed a decrease in rpm over time then it just started dying? In some older cars there is a small screw on the throtle body that regulates idle that may be missing it. In new cars with mostly eltronics there might be a fuse thats blown or a relay that is messed up.
I am not an expert, but those are somethings to look at. If anyone knows that I am wrong feel free to let me know. and this guy.