Stop using single-use water bottles.

Purchase a reusable water bottle and bring it with you everywhere you go. Anytime you run out, refill it with filtered or tap water. You'll not only wind up spending less money over time, but you'll also contribute to a decrease in the enormous amount of plastic water bottles that are dumped in landfills and the ocean.

 Refuse to use plastic straws.

A large portion of the plastic waste that comes from straws is harmful to marine life. Spend money on reusable metal or bamboo straws, or just forgo the straw when dining at a restaurant or cafe.