Central Station & Trains, Amsterdam
There are only two dangers while in Amsterdam:
First, while you are in the Central Station watch out for smugglers and pickpockets. They are easily identified. The same advice is while walking on the streets, don't pay any attention or begin a dialogue to people who want to sell you coke or hash, they can walk for miles with you trying to persuade you. The second danger is that you have to look down in order not to walk on poep: dog's s..t in dutch!! Especially at night, where you can't see them clearly.
The junkies and vagabonds at Centraal Station. They may offer to help you put coins in the left luggage lockers or ask you for a newspaper - anything to engage you in conversation before begging for money. This is not a safe place for anyone on their own. Travel with someone and stay with them - even befriend another traveller and stay together - particularly if you need to be at the station at night - OR stay on the platforms and don't go downstairs - the police manage to keep them away from the platforms...
Recently a lot of robbers have been active on the trains from Amsterdam to Schiphol (and back) and on the different train stations. They let some money fall on the floor, point in a certain direction, distract you in other ways and run with your suitcase or other luggage. So be carefull out there. No need to say that you have to be carefull for pickpockets in the city as well!
When leaving Central Station you will be approached by young people offering to find you accomodation. Do not engage them in conversation.
Also some people offer to assist in buying tickets from the machines for travelling on the trains. They often charge you for the ticket you want, and when you look at the ticket you will find it is a discount ticket for which you require a student pass.
They have made a few guilders at your expense, but you will need to go and purchase new tickets from the ticket desk
keep your eye on your stuff on central station
PLUS: dont walk on the red cycle paths: you'll drive local cyclists nuts and they wont brake! (at least i dont ;-) )..it hurts to get run over by a dutch bike..