It is nearly impossible to drain a water tank completely. If you can get it mostly drained, it won't freeze to cause any damage. If the tank has a opening on top, you could open it, cover it with screen and let the last of the water evaporate. But if it is in a warm humid place or it doesn't evaporate fast enough you may have a little mess to clean out. You can use a water freshener .
Disconnect your water pump and get any water out of the pump. Water pumps will freeze and this can damage the pump if there is water left in it. Drain your water heater as well.
Attach a blow out plug with a tire type valve on it to your water input valve. Then one at a time, open a faucet handle, turn on your air compressor and it blow out the line. This will remove any water and crud in the line. Open the next faucet a little bit just before closing the previous one. You don't want all lines closed with the compressor running because it could blow a line. That's not good. Always having one open a little bit will let that pressure run through. Close off the previous faucet and fully open the next. Repeat this until all water lines are cleaned out. Shut off the compressor before closing the last faucet.
Remember to drain or disconnect the outside shower. This is usually the first one to freeze and break.