BE AWARE!! of people offering taxi services in the arrival hall, they will rip you off... in front of the airport there's the only official taxi pick up place it is safe and controlled.
Not all trains go to Amsterdam Central Station. Read the info boards before you take the escalator down to the tracks, to avoid running around like crazy ;-)
This is a very nice airport!! Just be careful with the people who pretend to be a taxis drivers but they are just people with regular cars trying to make some money.