Etiquette

I was playing a capitals game yesterday, and killed a player who had only 1 in his capital. In the game chat, they admitted they didn't understand the rules of the capital game, and the other players mentioned that I should have let him have another turn to re-inforce his capital - that this was site etiquette.
I've only been on here a few weeks and din't know this was the case.
So, are there any other site etiquette rules I should be following?

(I'm aware suiciding is regarded as a no-no)

I don't want to be annoying people!

What you did was fine. It is good etiquitte to let a player know he/she is doing something wrong, but unless all players agree to leave it for a turn to let someone reinforce, you must do whatever it takes to win or someone else will.

Yeah, it's best to inquire in the chat to make sure the other players will follow the etiquette and let him reinforce his cap.

NO SUICIDING!
(or quitting.)
HAPPY HALLOWEEN!