The train is definitely the best way to get into town from Schiphol. As you leave the station check out the massive multi-story bike parking on the right hand side. Depending on where your hotel is you may then need to grab a taxi from there.
Water bus tours are quite good, as is the Anne Frank museum. Some of the private museums along the Damrak are really quite odd.
Red light area is properly grim.
The Dutch are pretty intolerant of misbehaving stag parties now so just be careful. They were talking about making you produce a form of local ID if you wanted to sample the shrubbery. Dunno what became of this.
Trams and bicycles have an absolute, unquestionable, anointed-by-God right of way.