1. Instead of paper towels we use cloth towels. The ones I have are crocheted cotton ones that my grandmother's friend made. If I spill something in the kitchen, I wait until I am done cooking then clean the whole counter-top with one. If there is a big spill, I use an older bath towel we keep around for such a purpose.
Result: We have bought a grand total of two paper towel rolls in the past year and are not even halfway through the second roll. (We do realize there are somethings that just need a paper towel)
2. No plastic baggies! have some reusable plastic containers for sandwiches (the black, round Chinese food containers are perfect for sandwiches, we also have some square ones). For other snacks for our lunches, we use other reusable containers and we save the plastic containers we buy butter, sour cream etc in.
Result: We moved in with a 3/4 of a box of freezer bags and we have used them for traveling mostly.
3. Recycling! We have a container for trash, plastics/aluminum/glass, and papers. We line the recycling ones with a plastic bag, but don't throw it away (essentially it doesn't get dirty if you rinse the items).
Result: Less "trash", fewer trash bags used. We are on our third box of trash bags.
4. Use cloth grocery bags. I started with using backpacks and whatever other cloth bags I have around the house. At my bridal shower, several people gave me gifts in a reusable grocery bag and I started using those. I try to keep some in my car, in case I go to the store on a whim. And you can use them for other kinds of shopping too! i.e. clothes shopping. When I grocery shop, I try to bag stuff myself at the self-checkout. Baggers tend to put one thing per bag and end up using the plastic bags for the over flow.
Result: I rarely use plastic or paper grocery bags, when I do I return them to the recycling bin at the store. I know some people need plastic bags for their pets, but I suggest using mostly cloth bags, and a few plastic bags.