New Bridge Partner and Etiquette
It's tough for the Type A personalities so often attracted to competitive games like Bridge, but all criticisms of partner should be reserved until after the match. I suggest noting to your partner "Make a note of that hand, and we'll discuss it after the game." One or two violations per game, that accept such a comment with a positive attitude, can be tolerated in a partner - any more than two you should be looking for a new partner, as the problem will get worse not better.

All criticisms of anybody else in the room are out of bounds - give your partner one warning and then have a word with the director. If you partner persists in this behaviour during the game look for another partner, and report offenses to the director as they happen by calling him/her to the table. Otherwise you are liable to get branded by other club members as a cohort of like mind.