Is it cheaper and more convenient to buy tickets for activities online before we go or can you get discount coupons to attractions from the hotel etc? We are staying at the intercontinental. We already bought tickets for Anne Frank since we know that can sell out.
Depending on how long you're staying, either the IAMsterdam card or the Museuamcaart could be a good move.
IAMsterdam card has unlimited metro (which you need from IC), entry to selected activities, and a canal tour. I think they have versions from 1-5 days.
The Museumcaart is good as basically every museum in the Netherlands for a month, but doesn't have the other perks. You can only buy it at select museums.
Regardless, for certain things, you'll want to book a timed tour in advance - specifically Hieneken and Van Gogh (both recommended activities).