Asanee -

I'm arriving by train from Chiang Mai, reading your post it struck me that it is better to get off the train at Don Muang and take the 555 or 554 to the new airport - easier than going into Bangkok and getting a bus from there.

But how do you catch it? Does it go along the road ooutside the station and can I just put my hand out and stop the bus?

Might sound a stupid question but I recall the area outside Don Muang as having about 6 million roads!

If I recall correctly, the bus stop is between the railway station and the airport, underneath the pedestrian overpass. Don't worry, the bus stop will be apparent and usually there are other people catching buses there.

You could also leave the train at Rangsit and catch bus number 554 or 555. I've never done this, so I can't tell you exactly, but I'm sure the bus terminal is near the station. Just ask when you get there. In my experience, the further you get off the beaten tourist track, the more helpful are the locals. Railway employees normally speak (at least some) English.