From the old Arab bus station in East Jerusalem take number 18 and go all the way till Ramallah. Have your passport ready, most likely you’ll need to show it at the checkpoint. If it sounds like much ado about nothing, bear in mind that if you weren’t a tourist, you’d have to get off the bus, undergo a search, cross the checkpoint by foot and only after all that get back on. Patience is probably the most valuable asset to carry around in the Middle East. Although Ramallah and Jerusalem are only 15 km apart from each other, it took me around 40 minutes one way, most of it standing and waiting.
The city itself is not huge (approx. 65k inhabitants), but since it serves as the de facto capital of the Palestinian National Authority, it gives you an almost-cosmopolitan feel. To most of the destinations you can easily walk, the city center is quite small. Although only a few historic and religious sites are present here, it’s one of the most vibrant places in the West Bank, so just sit down, have a drink (enjoying the religiously relaxed atmosphere here than elsewhere), relish local food and meet some locals over an “Argila” (flavoured tobacco water-pipe).