These few items have helped me avoid hundreds of plastic bags, dozens of plastic utensils, hundreds of plastic and paper cups, dozens of take away containers, and packs of kleenex/tissues. Not only does this reduce how much waste goes into landfills and incinerators, it also reduces the energy consumption of producing these products in the first place.
Its a small contribution to this planet, but I feel empowered doing my part. When I see images like this one, my heart swells and I am compelled to do everything in my power to reduce my footprint.
Perhaps I can encourage you to join me in the practice of keeping a bag with you whenever you go out (a plastic bag folded up fits inside a pocket quite easily), and/or to take a reusable cup/container/utensil/etc when eating out or ordering take-away.
My father is an economics teacher and I have been learning about the way money makes the world go around since I could talk. The basic principal that drives our free-market economy is supply and demand. If we reduce the demand for plastic bags, plastic cups, styrofoam take away containers, etc. - we will reduce the supply, the production, and therefore the existence of these vile things.