What is best way to get from XI'an airport (XIY) to Citadenes Central Hotel?

You can take the airport shuttle bus Bell Tower Line to reach terminal at Melody Hotel near the Bell Tower. Then you can walk along the West Street to west side to the first T road crossing road. Then walk to the south road till you see your hotel.
If you cannot find the direction easily, you can ask the Melody Hotel staff to find the hotel easily.