Book FAR in advance has helped me out a bit.
You could also fly into an airport an hour or two away. (ie flying into Akron, Ohio instead of Cleveland sometimes makes it cheaper, sometimes more expensive. You can't be so choosy as to times of the day when you fly into a smaller place)
I have to fly into Ft. Lauderdale (where my dad lives) and then get to Disney, so we were considering flying from Ft. Lauderdale to Orlando after the visit but FORGET it, it would've cost the same thing it's costing me to get from Charlotte to Ft. Lauderdale. So, we're renting a car and driving....then we'll drive back (again, we have to anyway) and fly back to Charlotte out of Ft. Laud.
I guess if you aren't driving the whole way and need to rent a car anyway, it might be worth it.