4 full days itinerary in xian.

Since you have four days, you are suggested to spend two days explore some main attractions, such as the Terracotta Warriors Museum, City Wall, Shaanxi History Museum, Big Wild Goose Pagoda, Muslim Street, etc. For the other days, you can extend your trip to other places, like Huashan or Luoyang. You may either explore the city on your own using public transport or contact a local travel agency to arrange a guided trip for you.

Thanks.