"Take only photos and leave only footprints" should be the mantra of any serious camper, hiker, climber, or biker. Keeping the great outdoors pristine only requires a few changes to your routine and can have major benefits for years to come.
One of the great problems of camping is the waste you can produce: the wrappers on energy bars, the plastic in water bottles, or even the tags on new gear. Look your gear up and down before departure to cut out trash wherever you can: put items in renewable containers when possible, don't buy food that comes with a lot of packaging, and don't bring supplies like toothpaste or bug spray that are nearly empty.
Cutting down on your camping footprint leaves you with more space and requires fewer trips and fewer disturbances to the ecosystem. Look for tents and sleeping bags that are ultra-lightweight, or go a step further and replace your tent and sleeping bag altogether with a lightweight hammock that's easy to set up and take down.
One of the core problems of camping is that it introduces wild animals, from bears to chipmunks, to the idea that humans are a source of food. The easiest way to prevent this is to bring food that doesn't require complex preparation and cleaning, lowering the chance of leaving food out or spilling it. Look for one-pot meals, no-spill foods, and safety containers to keep food in good condition without spreading it through your campsite.