It is wajib to hide your private parts in the toilet at all times. It is also wajib to wash away the najasat first after urinating. Clean our bowels from water or dry pak paper.
It is Mustahab to enter with your left foot and leave with your right foot. Urinating before sleeping and namaz or Salaat or prayer is also recommended.
Urinating on the road side or under the shade of a fruit tree is not recommended. Eating while you are reliving yourself, taking longer then necessary, talk in the toilet are all Makruh acts.
It is haraam to face the Kabba or keep your back toward it while reliving ourselves. Using sacred things to make yourself pak is also prohibited. It is Haraam to relieve yourself at someone's house without asking their permission. Also in blind alleys without asking the people who live there. On a grave or sacred places like a mosque.