But there's also something far more subtle – but equally fascinating – to watch for on the big day, as well as in the months leading up to it.
In the course of royal affairs, the Queen, along with others in the family, use some little-known secret cues in their social dealings. First and foremost, when Her Majesty is ready to wrap up a conversation or social event, she switches her handbag from one arm to another, signaling her handlers to move in and usher her away.
"It would be very worrying if you were talking to the Queen and saw the handbag move from one hand to the other," royal historian Hugo Vickers tells PEOPLE. Luckily, they'd let you down easy.
"It would be done very nicely," he says. "Someone would come along and say, 'Sir, the Archbishop of Canterbury would very much like to meet you.'"
And if the conversation is especially painful?
When Her Majesty is truly keen on making her escape, she makes the more dramatic gesture of spinning her ring, indicating that her staff should move her along, pronto. Placing her bag on the floor sends the same message.
And when she takes official meetings in Buckingham Palace, she's got the luxury of wrapping them up with a discreet buzzer that signals the staff outside to the open the doors and escort the guest out. (Said guest must also have an understanding of royal protocol and take the first three steps away from the Queen backwards, so that he or does not turn his back on her).
THE PRINCES' PROMPTSIt's not just the Queen who employs these social cues and courtesies.
Prince Philip is known to do a particular sweeping motion when he's meeting people in a lineup in order to avoid getting stuck in a lengthy chat. As he takes someone's hand, he might say, "How's it all going?" and as he does so, his hand swings from left to right, and by the time you've answered the question, you're about eight feet behind and he's moved on.
Then there's Prince Charles, who likes to end things on a humorous note in order to keep moving. "What they all do is try to find a quick joke to leave it on," notes Vickers. "Prince Charles has a quick 'ha ha' and that enables him to break the conversation."
But what of Charles's well-documented habit of fiddling with his cuff links? (Like father, like son, Prince William has picked up this tendency as well). Vickers says he is unaware of whether Charles and William have tricks similar to the Queen, or whether the fiddling is simply a nervous tick.
Either way, we'll be watching.
Reporting by Simon Perry