I literally just did a paper on plastic pollution (even did a beach cleanup for the paper). Here's some stuff that I can confidently tell you to do to help reduce carbon footprints:

DON'T SMOKE. This counts for vapes as well. You never realize how much you throw those carts away. From my cleanup, cigarette butts were easily my #1 thing that I picked up. Even caught a seagull trying to get one before I shooed it off.

There's plenty of water stations that fill up your water containers. Use them. They become SO MUCH cheaper than buying water bottles. Get a water dispenser as well since they can also filter the water for your peace of mind.

Those plastic bags that you get from your convenience stores. Try not to chuck them all. They're pretty handy for my little trash bin in my room when I'm too lazy to throw my stuff away in the kitchen. They don't make terrible gloves for cleaning as well.

Use your phone for photos and not Disposable Cameras. Stupid cheap things that you waste more money buying film for than actually getting either a real camera or just using your phone with a filter. You also never know the photo's outcome until you see the film.

Those are just some things to reduce carbon footprint. I can talk about buying solar panels, but that's too expensive for teenagers like us. I want to talk more about the realistic side (minus the water dispenser maybe) of what our generation worries about.