Well, all environmental problems are cause primarily by overpopulation. So, make sure you eat an organic diet and keep the unnatural chemicals you put into your body at a minimal. Then kill yourself in an unpolluted field so your body can serve as fertilizer and stop burdening the planet with consumption.
Oh, wear natural fibers so they decompose along with you.
“Being green” isn’t a solution, it’s a control gimmick that preys upon people’s will to do good. Our social design is fundamentally flawed and will continue to drain resources until its inevitable collapse. You want to help the world, it’s going to take more than recycling your soda cans.
For your school, though? I don’t know, you could teach yourself and people you know a skill that replaces the use of a product. Think about that. It’s always best to be able to do the basic things without the need of anything you have to buy.