Leave Paddington at home. While a furry cameo appearance was fine for the Jubilee, this is neither the time nor the place. And if you're considering packing a marmalade sandwich, make sure you eat it yourself, far in advance of Westminster.
Guard your wristband with your life. Remember that it will allow you to leave to seek food, shelter or the many portaloos without losing your place in the queue.
The route takes you past the Covid memorial, so even if you are not a devout royalist, you may need to prepare yourself to encounter some raw emotions. The Samaritans are on site if required.
As with anything to do with London and distracted tourists in particular, look out for pickpockets.
Do not bring tents, seats, big umbrellas or anything that will prevent you moving, albeit slowly, forwards.
Dress respectfully. This season, the hottest colour is electric pink. This is not the day.
Expect to be interviewed by a combination of broadcast and print media. There is no bigger story in Britain right now. Many of the subjects, particularly if they have some sort of union jack clothing will have been interviewed many times.
You don’t have to make small talk for the whole time. But try and interact with your fellow queue participants and not spend it glued to your phone watching the BBC news (dubbed ‘Mournhub’ by one wag).
Don’t get into a discussion about the draconian implications of a right to protest following the arrest of someone shouting against Prince Andrew. Discussion will come later.
If you push in, expect the fury the like of which you will have never seen.