Its not really what you are bringing into the country you should be concerned about, its what your bringing out of the country that will get you in shit...DO NOT CROSS ANY BORDERS WITH DRUGS!!! Even EU countries, just do not do it, if you get bust we will be sending you emails in jail. And if your into more than weed,hash or shrooms ( the tolerated drugs) your all good, but if you get into the heavy stuff like crack and coke your asking for trouble.
I would recommend you do not buy from street dealers, if you have seen some of my other posts you 'll see why.
Things can go from bad to worse
If someone speaks to you in Dutch, do not yell back at them in English saying you do not understand, just try and learn a few word to get ya by.
There are a few posts here on Amsterdam so go through them and you will find lots to so whuile your there. Just be careful, and use common sence.
Hope that helps some wong!! if you need anything answered let me know. B)