Be sure that you do not leave a fire unattended and when you leave the campsite be sure the fire is totally out. If possible, use water to put out the fire. Place your hand near ashes to be sure they are cold. Be careful of fires near tents. Use a trail stove for cooking.
Suitable firewood is often in short supply around a campsite or lean-to.
Do not cook or prepare food in lean-tos. Spilled food attracts animals that come later. It is very dangerous to use a stove in a tent and to cook in such close quarters. Take out what you brought in. Clean up the trail and campsite leaving it better than you found it.