What do you do with all of those packing and shipping materials that end up piled high in the dining room? There is on thing you shouldn't do with them. Throw them away. There are lots of ways to avoid them becoming landfill.
You have no control over how a package that is shipped to you is packed. But you do have control over the packages you ship. Try to find appropriate sized boxes so you don't have to put more filler than needed in. You'll save money, and you'll save some greenhouse gasses? How?
It may seem miniscule, but every little bit of extra weight in a package means that the vehicles used to haul it needs to use more fuel. If you make your package as light as possible, and others take the same measures, fuel will be saved.
Another way to reduce when it comes to shipping is to ship directly to the recipient. Do you order gifts online for friends and relatives you live far away, have them shipped to your home, wrap them, and then re-ship them to the recipients? You're doubling the carbon footprint of that packages travels.
If the company you order from offers gift wrapping, let them wrap it and send it directly. Or, if you're buying for kids who live far away, let their parents know you are sending some gifts and ask if they wouldn't mind wrapping them for you once you arrive. My in-laws do this frequently.
Packing and shipping materials can be reused over and over. I have a spot in my basement where I have broken down boxes, bubble wrap, air pillows, etc from items that have been shipped to me. When I need to ship something I never need to buy anything new (except packing tape once in a while).
What if you don't have the room to store these materials or you end up with more than you will ever use? Giving it away is easy.
Many packing/shipping stores will take things like packing peanuts, air pillows, and other fillers. They won't pay you for them, but it's worth it to donate them to keep them out of landfills.
If you have any friends who are ebay sellers, they will probably happily take these materials off your hands.
Another way to give these things away is to list them on Craigslist or to Freecycle them. If you have a collection of packing/shipping materials there is someone out there who wants them, and that someone is checking these places to see who has them.
Last year, as the boxes came in with online purchases, I threw them all in the downstairs shower (we never use it - it's more like a closet). After the holidays, I put it all together and listed it on Freecycle. Within a couple of hours, someone had come to my house and collected it all. It felt really good to know that all of this stuff was going to get reused at least one more time.
If any of these items truly are unusable, say a box has just gotten to beaten up to reuse, make sure it hits the recycling bin and not the trash can.
It's tempting during the busy holidays to just get these shipping/packing materials out of our way by sending them out for the trash men to pick up. It takes extra effort to make sure they end up being used and reused and disposed of responsibly. So decide now to be make a commitment to being responsible with them so you won't be tempted to put those evil packing peanuts in the trash can.