I came back from Amsterdam with the OH last week, was an amazing trip went for 6 days and wish we had more time.
Not sure how your getting there, but if your flying, I would recommend the train to central (somtimes written as centraal) station. TRY NOT to buy tickets for the trams on the tram itself, it's cheaper from shops. Everyone is friendly and nice and everyone speaks English, don't be afraid to ask directions.
I would highly recommend the Ann Frank house, but go late, around 8:00 otherwise it's packed and you will queue for 1-1.5 hours getting in, check the closing time, but I think 8:00 was when we got there.
The van gough is also pretty good, but expensive and you will need time.
The chips are great!
There us a great little shop called pylons, if your into quirky colourful gifts it's located on Leidsestraat? in the leidseplein.
As for the red light district, 10:30 onwards is when it livens up a bit, during the day it's not as interesting. Lots of sex shops, with a huge selection of things, unfortunately I have only recently told my OH that I quite like her being the dominant one, we didn't really have time to get anything useful, don't buy cheap handcuffs they hurt! Lol.
We went to the sex museum, it was over rated, but maybe worth going for just saying you have been. Then there is the erotic museum, I think that's what it was called, we only looked in the entrance to this one, but it looked better than the sex museum, we just didn't have the time.
Just have fun, it's a great city with loads of experiences