Do you have any pearls of wisdom for a new-starter who has spent his entire career as a freelancer?

I'm a bit concerned that I'll be embarrassingly unfamiliar with the conventions and culture of working in-house, in an office.

I'm confident about the job, but I'm so used to doing it from my house, in my pants, that I'm scared of committing some massive office faux pas.

Advice received so far...

Don't take smelly food.

Don't assume the tea and coffee is free.

Ask your boss if you're unsure of anything, don't pretend you're ok only to then need to ask how the photocopier works in two months.

Decide on day 1 whether you're "in" or "out" of the present-buying system and stick to it. Don't chip in for some and not others.

Anything else I should keep in mind?