Don't shortcut switchbacks. This causes erosion and damages the trail and trail environment.
Follow the "leave no trace" ethic and leave your campsite and trail cleaner than you found it.
Don't use soap in streams. Wash yourself, utensils, or clothes away from all water sources.
Where privies are not available dig a "cathole" at least 6" deep and cover afterward. Do this at least 100 yards from any water source or camping area. Do not leave toilet paper above ground.
Treat water with iodine tablets or boil or filter water before drinking.
Animals frequent camping areas. If staying overnight, hang food at least 10 feet above the ground;never leave food in a tent.
Use campstoves for cooking. Use only downed wood for campfires and keep them small. Never leave fires unattended and always extinguish them with water. Some areas have fire bans along the trails and shelters- check with the Rangers, look for signs.
Know your route and allow sufficient time for your trip.
Do not overextend your abilities.
Tell somejone your hiking plans.
Dress appropriately. Be prepared for sudden and extreme weather changes.
Carry sufficient water and food and first aid supplies.
Hike with a companion.
Enjoy your hike!