There's a couple of adjustments that can be made. I would start with the throttle cable.

Also, this acutally brings up a question: has it always idled low, or is this something new?

Usually a sudden idle change like you described can be caused by a clogged fuel filter. You may want to replace that if you haven't done it since you've owned the car. Your fuel pump could also be dying... just some other options to consider.