Choose energy efficient appliances.Lets use modern mainstream personal computers as an example.These days they consume enormous amounts of electricity (200W or more),many people don't need the enormous computing power supplied by them.Laptops are a more energy efficient alternative.You can also get green desktop computers that use less than 50W.For these you will need an operating system that is not excessively resource hungry such as Linux
An LCD computer monitor uses less energy than a similar sized CRT (Cathode Ray Tube) monitor.The CRT monitors are the older style ones that are box shaped and often have curved screens.
Choose energy efficient lights such as Compact Fluorescent lights and LED lights.
Did you know that 35W IRC lights are a direct replacement for 50W Halogen lights? For a similar brightness you get roughly a 30% or more saving in energy!
Make sure your appliances are in good working order,for example - the fridge is sealed properly and your air conditioner has a clean filter.
Switch things off when they are not in use.
Some devices in your house are power vampires and constantly draw a bit of power.Over the course of a year this adds up to a significant amount of energy.Such devices can include DVD players,TV's,PC's,printers,stereos and many more.You should be able to buy a set of switches that cuts power completely to these devices.You will need to shut down the device first according to the instructions before you can cut power to it.
Use your computers power saving settings.
Favour things that are not powered by electricity or fuel,eg. manual lawnmower and a manual treadmill.
Use a lower flow shower head to save on hot water.
When washing clothes use cold water.
Wash only on a full load.
Use a dishwasher only on full loads.
Heating/Cooling
Insulate your house if you use a heater or air conditioner.
If you can handle it ,don't use your air conditioner too much.Air conditioners require enormous amounts of electricity.A more efficient way to keep cool is to wear an ice collar such as the ones professional sportspeople use or in less severe weather you can just use a fan.
Turn down your heater a few degrees and put on some more clothes.
Don't leave the heater on when you are warm in bed.
Close any rooms that you don't use so that they don't get heated or cooled unnecessarily.
Keep your fridge and air conditioners in excellent working order at all times as they can generate very potent greenhouse gases if not working right.
Cooking
In general it is good to keep lids on pots and not boil more water than is necessary.
When boiling some foods (eg.rice,pasta,potatoes etc) heat can be cut 5 minutes before cooking is normally finished.The saucepan/cooking utensil is then covered with a lid and the food will complete cooking under its own heat in approximately 8-10 mins depending on room temperature.
Pressure cookers are one of the more efficient ways to cook.
Let larger portions of food which come out of the fridge warm up naturally for 15 minutes before further heating.
To defrost food move it from the freezer to the non-freezing section of your fridge one day before you need it.
Try to cook for more people at the same time rather than individual meals.
Oven cooking can be very wasteful as a lot of heat is lost,consider other options such as pots on the stove.
If you use your oven a fair bit consider getting one that is heavily insulated and fan forced to cook more efficiently.
Avoid opening the oven unnecessarily.
If heating food from the fridge ,heat only what you need.
How does it help?
Savings in energy usually translate into decreased carbon emissions due to the large number of coal burning power stations.Saving gas also means decreased CO2 emissions.CO2 is often produced when gas is burnt.
Other advantages
Pollution is minimized.
Appliances usually last longer when used less.
When appliances are turned off there is less risk of fire.
You need less cooling when energy is being saved.
When you use manual devices you will notice improved strength and fitness.
Letting food finish cooking under its own heat reduces the risk of fire.
As already mentioned you save money.
Occasional sweating can be a healthy thing.
Example
Below is an example of energy savings by a family of 3 in Melbourne,Australia just by applying some of the above suggestions.
Their electricity supply comes from a coal burning power plant which means that greenhouse gas emissions are closely related to the amount
of electricity consumed.Electricity consumed was cut by approximately 25% corresponding to a cut in greenhouse gas emissions by approximately 1 tonne a year.The saving was over $200 AUD per year.A nice reward for being kinder to the environment.