Bring plastic bags to hold your garbage and pack it out. Leave no trace, as they say. Do get yourself a topographic map and compass and learn how to use them before you head out. Know your limitations. You should not attempt to climb cliffs or steep terrain without adequate equipment, conditioning, and training.
Accidents can be fatal.
Carry a minimum of one gallon of water per person per day just for drinking, two gallons in hot weather or if you are planning a strenuous trip. You will need additional water for cooking and hygiene. Coping with the weather That old desert sun can damage eyes as well as skin. Wear a hat and sunglasses and use sunblocking lotion liberally. Temperature changes of 40 degrees within 24 hours are common.