Listen, even old grumpy country folk agree. You may not be able to buy fresh greens and fruits in the dead of winter (at least in parts of the midwest/east coast). Just don't buy, for example, blueberries from South America (plus, they are packed way before appropriate harvest time and taste awful - I think).
Save leftover hardware (screws, nuts, washers, etc.) from pieces of self-assembled furniture. Just toss them into a bin in the garage or basement. When you need a screw, check your extras before going out and buying an entire box of new hardware.
You know how you can't take a water bottle through airport security? Empty it out before you go through, and just refill it on the other side from the water fountain. Much better than throwing it away and buying a new bottle a few minutes later.
For most recipes, preheating the oven isn't actually necessary and uses up more electricity or gas. Turn the oven on when you are ready to put your food in, and you can conserve more electricity gas.
Keeping your tires inflated to the proper pressure can improve your gas mileage by up to 3.3 percent. It's also safer, and will make your tires last longer (which ultimately results in less waste).
Look for biodegradable doggie poop bags for cleaning up after your pooch. There's a lot to clean up after over the life time of your dog. Help it all return to earth faster by avoiding non-biodegradable plastic baggies.
Follow in the footsteps of blackle.com and make your website's colors darker. This can help save energy. For example: If you've got a centered layout (like TipBin), you could make the sides of the page darker. Every little bit helps!
Open your curtains in the morning to let solar energy (aka sunlight) in to warm your house, and close them at night to help keep it in. Sometimes it's tempting to close curtains during the day to darken a room, but remember that you're wasting free solar energy.
If you want to green your home by adding/changing insulation look for companies that sell reclaimed insulation. You get to save energy twice! Check the link below; they sell all over the country.
Save your plastic easter eggs for next year. One bag of plastic easter eggs will last you many years if you gather them up and save them. Just add new prizes (we usually use small pieces of chocolate and money.) If your kids have outgrown them, pass them along on freecycle. There's no need to repurchase them every year.