Stare vacantly into the space directly in front of you at all times, or stare at your phone in your lap.
Under no circumstances attempt to make conversation with those around you.
Stare angrily at the person listening to loud music which the whole train can hear. But of course, don't approach them about it.
If you need to get past someone, just mutter "Sorry, could I just..." and squeeze past. Never raise your voice more than a faint utterance.
In the stations generally, stride with purpose, even if you haven't the faintest idea where you're walking. No one likes a dawdler interrupting their well rehearsed march to the escalators.
Don't stand on the left hand side of the escalator, that's where the fast people walk up.
This is the way of the British.