Buy one of the plugin power meters. Aldi had one for under $15,...

Buy one of the plugin power meters. Aldi had one for under $15, your store may have one. Otherwise plenty of them on fleabay.

Use it on every appliance that is plugged in.

The biggest consumers are heating and cooling, followed by pumps/compressors. You use gas for water heating, what about cooking?

Air conditioner, you say you don't use it much, but exactly how much?

Plasmas are a killer, the newer ones are more efficient, but still consume alot.

Older fridges can be very inefficient. If the door seals are gone, they will be running 50% of the time. That could be 5-8 kW a day.

Do you have a swimming pool? The pump chews alot of power.

Standby current can be a sneaky user. Check what the TV, stereo, video, video recorder draw on standby. Also anything else that is plugged in all the time, such as the microwave.