Whatever you are doing in the outdoors, hiking, biking, etc., it is important to stay on trail. Going off trail can damage trailside plants, flowers, and small trees. Some things may not grow back if they are trampled. If you are staying overnight in the wilderness, only camp in designated campsites or on a durable surface. Leave No Trace states that "good campsites are found, not made."
Before leaving a campsite or pit stop on trail, pick up any garbage that you see and carry it out. If there are no bathrooms available, find a spot about 200 feet from trails, campsites, and water sources, and dig a hole 6-8 inches deep for human waste. Remember that if you pack it in, you must pack it out.
While on your adventures, you'll find a lot of beautiful treasures, but make sure you leave them how you find them. Taking plants, rocks, or historical items out of their enviroment is harmful and will also take away the opportunity for other visitors to enjoy them. Taking a photo of the things you find in the wild will be just as great, I promise.
If you plan on cooking outdoors, use a stove when you can. Stoves create less of an impact on the enviroment and are easier to cook on than a fire. If you do want to have a campfire, make sure you check the fire and firewood regulations in the area. Don't build your fire up bigger than it needs to be, do not burn your garbage, and make sure the fire is completely out before you leave it.