1993 Mercury Villager no power to anything except headlight

I was putting a new battery in and accidentally connected the negative/ground cable to the positive terminal on the battery and vice-versa... I apparently shorted something out... But what? Nothing happens when I turn the ignition key... I have headlights so I know the battery is okay and juice is going to them... But I have no power windows, radio, blower, etc. And there is nothing (no sound) when I try to start the engine. What do you think I shorted out... What do I need to look at? ...I have a volt tester... What do you think I might have shorted/burnt out? All the fuses under the dash are okay. I don't see any apparent problem with other fuses.