Coffee shops, back in the day, before the Euro, I used to pick them by the music they were playing, but any more the choices are not as good and the weed has gotten very expensive. Others on here are on top of the best strains and where they found them, it always changes
There are a lot of Great Museums in Amsterdam, if your into culture and history look into the Museum card it will save you money and time
The vibe/feeling of different parts of the city as well as coffee shops change with the time of day, night. The Red Light district early in the morning before the city awakes is one of the older neighborhoods and has a beauty at that time of day that gets lost in the glow of the evening lights
Everywhere you look there is art, look at the buildings, lamp posts, bridges, and park furniture, check out the window displays. the center of Amsterdam is very much a walk-able city enjoy the way it is interesting on it's own
Hope I helped, you could tell us what your interested in and where your staying
