If you want to go to any of the tastings - martini, tequila, etc - you need to go to Guest Services and reserve a spot. We'd never been to those but I hear they fill up quickly.
If you want to have Tea with Alice (or Peter Pan or whoever they send to have tea with you and the kids), you need to go to GS and get those tickets as well.
DH went on a Galley tour, which he found really interesting. They have other tours as well. Again, get tickets at GS.
We've been to a couple of the, oh, I forget what they're called...but where they do cooking demonstations of one of the courses you might have in a dining room. Those are fun and I think we just showed up for those.
I just saw the 7-night Western itineraries posted recently here on the disboards. If you scan through them, you will see what tours or events are offered that need reservations and you can go to Guest Services the first day if you really have your heart set on going.
But, here's what I have learned: You cannot get to everything.

Some things may not be exactly the way they've been on past itineraries.

There are going to be 2 things going on at the same time and you will have to choose.

And how lucky are we all because we have to be flexible with those kind of decisions?
Still, planning is good because...at least with us...if we don't do some planning then we end up missing out on things we really want to see or do.
May we all be blessed with a good balance of planning and spontaneity!!!