It will be very, very cold. Wrap up warm and have warm, comfortable, waterproof boots for walking around sightseeing.
I find canal boat tours quite dull as you only see the bottoms of bridges and the sides of the canals. I think Amsterdam is best seen on foot (ex DP lived there for years and we made many holiday trips there after he moved away).
You must go to at least one cheese shop and enjoy tasting the samples (they are all over the centre). You must also eat double cooked chips with sweet Dutch mayo from a street stall! Herring from the street stalls is also nice if you like that.
You can buy all the typical Dutch cookies, apple cake, Hagelslaag (sprinkles for buttered bread), etc. in any supermarket as well as cheeses.
My favourite museum in Amsterdam is the Van GOGH museum. Book online in advance.
There is a lot to see, old churches, architecture, etc. just from walking around and getting a feel for the different neighbourhoods and seeing what most interests you to visit. It's a tiny city so you can walk everywhere (or get a bike if you feel confident).
Café Wildschut near the Museumplein is great for watching the world go by, and it serves food all day. Kantjil & de Tijger restaurant is also great for Indonesian food (a former Dutch colony) but you need to book.