During play you shouldn't speak to your opponent, other than offering a draw, or announcing j'doube. Save all comments about moves until after the game, then by all means move to a skittles room or pub to go over the game with your opponent. Punch the clock after you make your move as your opponent is not obligated to remind you, nor are you to remind him.
OTB etiquette

Depends on the atmosphere, really. Generally don' speak to your opponent, but sometimes I'll have an opponent whisper "good move" under his breath and stuff like that, and that's probably okay (though I highly doubt most good players do stuff like that). As for time management, that's up to you - all the time on your clock is yours to do with what you wish.

I've said, "good move" more than once in a tournament setting.
Surprisingly, this has never upset my opponent.

Thanks guys:) Silence, save for "draw" offer, "j'doube" and...I assume ...announcing 'check', or is that considered insulting?

During play you shouldn't speak to your opponent, other than offering a draw, or announcing j'doube. Save all comments about moves until after the game, then by all means move to a skittles room or pub to go over the game with your opponent. Punch the clock after you make your move as your opponent is not obligated to remind you, nor are you to remind him.
I don't recall a rule or piece of etiquette that disallows pointing at the clock to remind the opponent to hit it.
I sometimes have done so, but usually just once per game (worrying about the opponent's clock habits shouldn't be very high on my in-game agenda, as I see it).

There isn't a rule or piece of etiquette that disallows pointing at the clock to remind the opponet to hit it, nor is there a rule or piece of etiquette that requires you to remind your opponent to hit it. Every serious OTB player I know will sit there until the cows come home or the opponent realises he forgot to hit his clock and punches it.
However I can see why you question my comment. Let me clarify:
"Punch the clock after you make your move as your opponent is not obligated to remind you, nor are you obligated to remind him."
I am - at last - planning to move to the world of OTB at a club. However, it has been 30 years since I played OTB, except for, literally, one casual game per decade.
What do I need to know? Is it against the rules to speak to your opponent, for instance? If he makes a good move, is it okay to compliment him or her? If you make a poor move, is it bad form to say, 'oh oh, I stuffed up'? etc.
What about clock management? Anything to be aware of there?
Anything else to be aware of?
Thanks in advance!