Lighting doesn't typically account for much of your electricity bill. Obviously LED or CFL will use less than incandescent or halogen lights, but not to the extent that would make such a difference.
Are your major appliances similar to your brother-in-law's? The fridge, for example, is a big culprit.
Another potential source is "vampire power" which is the energy that your devices use when they are supposedly off. Standby modes often drain a bunch of power, but it is impractical to cut power (with a lower bar switch) fully to things like your cable box as you could have to wait for your guide to re-load each time you use it (for example).
I have a device similar to this one (
http://www.canadiantire.ca/en/pdp/ha...-0529208p.html) that can help you find out how much energy each appliance, device, etc. uses. You can obviously plug your whole power bar for your TV, cable box, Blu-Ray, receiver, etc. into it to see how much each collection of devices uses.
Your fridge and washer you could also measure in the same way, but it is probably easiest just to use the government energy ratings for your major appliances to see how efficient they are.