Xi'an is an ancient city with a long-standing history and is known for being the capital city for 13 dynasties. Now, this city harmoniously combines its ancient charm with a modern atmosphere. It is also the jumping off point of the famous ancient Silk Road. As the most important city in northwest China, Xi'an attracts millions of visitors from all over the world with its historical relics, unique landscapes as well as its unique local cuisine.
Hereafter is a comprehensive index of Xi'an City Guide:

How to get Xi'an
By air
Xi'an Xianyang International Airport is the major airport serving the city and is the largest airport in the northwest region of China. The airport is located to the northwest of the city, between Xi'an and Xianyang(咸阳). There are direct flights from Xi'an to many major cities in China.

There are shuttle busses between the airport and the urban area with a 25 Yuan admission fee per person. Alternatively, at a price of 100 - 120 Yuan the journey can be made by taxi.
Here we will offer some information on shuttle bus in detail.

1. Line 1-between airport and Melody Hotel(西安美伦酒店) near the Bell Tower Tourists can reach many luxurious hotels in the city center by this line, like Hyatt Regency(西安凯悦饭店), Howard Johnson Ginwa Plaza Hotel(金花豪生国际大酒店), Bell Tower Hotel(西安钟楼饭店), Prince International Hotel(王子国际酒店)and City Hotel(西安城市酒店), etc.

2. Line 2-between airport and railway station, passes by Qinfeng Hotel(西安秦丰大酒店)and Jiefang Hotel(解放饭店), passengers can take this line to get to the Diamond International Hotel(西安钻石国际大酒店).

3. Line 3-between airport and Huoju Dasha(火炬大厦) in Xi'an Hi-tech zone

4. Line 4-between airport and Guomao Dasha(国贸大厦)in southern suburb, passes by Tangcheng Hotel(西安唐城宾馆)and Orient Hotel(东方大酒店).

5. Line 5-between airport and Jianguo Hotel(建国饭店) in eastern suburb, passes by Empress Hotel.

6. Line 6- is between airport and downtown Xianyang, which passes Caihong Hotel of Xianyang City.

Tips:
Though shuttle bus departing at downtown area leaves hourly from 6:00 to 18:00 for airport, the line 2 to 5 may be not in service after 15:00 or 16:00 except Line 1. While the departing time of bus from airport to downtown be according to the arrival time of flights. Even passengers of late arrivals can catch the service, but it will take passengers to Melody Hotel (near the Bell Tower) possibly not on to other destinations of lines above.
So if your hotel is not in the lime, you'd better first get to the Bell Tower, which is the center of Xi'an, and then transfer a bus or taxi to get to your hotel.

By Train
With a reputation as 'the Gateway to the West', Xi'an Railway Station is one of the most pivotal terminals of the domestic railway system. You can take a direct train to Xi'an from almost cities in China.
The station lies in the north urban area, so it will take you about half an hour by car from the downtown area. Buses traveling to the railway station can be found on every main street, and will only cost you 1 or 2 Yuan. If you choose to travel by taxi, the fare should be less than 10 Yuan (from the city center).
Purchasing train tickets can be troublesome for foreigners, as the ticket windows are usually crowded and have few English-speaking staff. One solution to such a problem is to ask for the ticket-booking service at any star rated hotel, who will offer their assistance for a nominal service charge. You are better off buying train tickets one week in advance of travel, especially during the peak travel seasons.