I used subway line 2 to get around and see the sites in xian. Similar to the beijing subway they have an ic card but the majority of my rides was 2 yuan one way. I got a free map from the shuyuan hostel that showed the stops and what was nearby.
Also, there was an extra check at the security stations whenever i had a bottle of liquids they either took the bottle and put it in a machine or made me take a sip the best i could figure is they are looking for molotov cocktails
By the way if you want to book your long distance trips the bus station near the xian railroad station had lon distance tourism buses

Things to bring:
1. lotion - due to the weather or the cheap brand of soap in the hotel, our skin got so dry and even itchy.
2. chocolate drink sachet like Milo - you cannot find Milo in their groceries. In case you might not like their food, at least you can take something at night.
3. Umbrella or raincoat, thick jackets, etc - even if your tour guide says it's going to be a sunny day. We brought a carry-all bag, and put all these stuffs inside. and leave the bag in the bus if we don't need them.
4. sunblock and chapstick