Pick up at nine in the morning than transfer to 

Terra Cotta warriors and horses museum (the 8th wonder of the world)

Banpo museum (a Neolithic museum with the site and relics of 6000 years village )

City wall ( the only well preserved city wall in China which was build in 600 years ago)

Moslem street ( with a lot of classical minority's snakes, a place where can satisfy your both eyes and stomach)

Terra cotta museum is the most attraction and must see. Banpo museum is what I highly recommended. City wall or Moslem street , you can choose one of them to cover or both. Time is flexible .