If you choose to have a campfire, you are choosing a very large responsibility. Your first step is to choose a location for your fire. If there is an existing fire ring, use it. If it is in a bad location, move it to a better location and clean up all remnants in its original location. Never place a campfire within the radius of the largest branches on a tree.
Fire can actually travel through the tree's root system and cause a forest fire.
Never build a fire close to a rock or other natural object where the fire will scorch the object and leave lasting impacts of your visit. Next, you'll need to collect firewood. Breaking branches off of a live standing tree leaves a very discernible and long lasting impact. Firewood size is very critical. Firewood should be no larger than an adult's forearm in diameter.