Also being from there and being back from a recent trip…
I’m recommending that you read the book “how Scots invented the modern world” by Arthur Herman. That will give plenty of context for what you’re going to see.
I think that everyone has posted great things to see and do. I’ll add a few things that I haven’t seen mentioned here.
My first thought is to book as much as you can in advance, especially some of the more touristy spots. Edinburgh castle and holyrood palace are at opposite ends of the royal mile.
I recommend that in Edinburgh you consider a ghost tour, and if Harry Potter is a thing, book one of those tours too. The Scottish National museum was great too.
Check out the Mackenzie poltergeist in greyfriars cemetery, and if you’re up for it, the entity tour.
One thing that we did last time in Edinburgh was
https://tartanbiketours.co.uk/ sea to sky tour on e-bikes. That will depend upon the age of your travelling group. Next time that we are back, I will do a longer bike tour with Johannes (owner of tartan bikes).
On the Jacobite express, the one that goes over the glenfinnan viaduct (from Harry Potter), it is often booked out for years. Scottish rail runs regular trains from Glasgow to Mallaig which takes exactly the same route. It’s one of the top train routes in the world for scenery and it can be a full day. If you’re into that sort of thing.
You might want to go to a football match but be sure of who you are watching and if you’re in the home or away end.
I personally like the open top buses to see things, but that’s mostly to get my bearings the first time I’m in a new city.
Parking is at a premium in Edinburgh old town. If you’re driving, although I drive standard there, it’s almost worth the premium for an automatic if you haven’t done right hand drive before. Learn about how to properly drive a roundabout. Yellow lights operate on a different cycle than North America (yellow before it turns green) which helps if you drive standard.
Get a euro sim for all family members. You can use airolo or similar, or just buy physical sims from Amazon before you go. People use what’sapp a lot.
Also check out concerts as sometimes you can get tickets to groups that you might not get to see here.
Hopefully that’s enough stuff just a bit different from what everyone else said…which was great.
You will want English pounds (standard pound sterling) in your wallet. Spend your Scottish pounds when you are in Scotland. Both English and Scottish pounds get used in Scotland, but Scottish pounds are not widely accepted in England and Canadian banks charge a premium to convert, if they convert them at all.
Try Irn-bru. A great place to get food is Gregg’s or a local bakery; pasty’s and sausage rolls etc. they even make vegetarian ones!
Ps it can be expensive. Wear Canada pins.