I'm glad we got a nice big, modern walk-in fridge that uses only a little power. You'll find plenty of lists of "how to save the world" in easy steps, and a lot of them are fiddly little things that it's a problem to remember and sometimes a pain to do. There's also the fact that some make a huge difference, others, while terribly worthy may be wiped out by that light-bulb you forgot to turn off last night
Here is a list of the more effective steps - that make the largest difference, if you want to re-use supermarket bags as well even better, but if you don't do those listed here, you're missing the more important tricks.
These are ways to reduce the amount of greenhouse gases, chiefly carbon dioxide, that you are personally responsible for releasing. Some are obvious, drive a car - carbon dioxide (CO2) comes out of the exhaust, some are less obvious, buying just one new shirt instead of two that you don't really need for instance saves on CO2 emissions in its production and transport.