An absolute must as Brenden hit on is GFI. GFI stands for Ground Fault Interupt if you didnt know. Those are the outlets that are required by building code to be placed in bathrooms close to sinks and such. If your an DIYer you could replace the existing outlets with GFI plugs. Make sure you get a circut tester and power down the outlet and then disconnect the wires and hook the GFI outlet up like the first one was. If your not that big on DIY
and the cost does not make a difference http://www.hellolights.com
) has a nice plug in GFI. It plugs into your outlet and then you plug your electrical equipment into that. This way if you have a failure the circut will trip at the GFI long before you become one dead aquarists or long before a fire starts due to a short circut.
Drip loops are also essensal. Basicly you should get into the habit of always running your cords so they loop down below the outlet. This way if water runs down the courd it will collect at the low point and not run into the outlet or close to the outlet.
Run the cords as cleanly as you can with zip ties. This will make everything a much cleaner install and also shorten the chance of unplugging something by accident or having something fall into the water, etc.