bury your head in the sand	ignore a problem or an unpleasant situation and hope that it will disappear
gain/get/have/take the upper hand	gain/get/have/take control or advantage over a person or situation
get/have your way	be allowed to have or do what you want
live and let live	used for saying that you should accept other people's beliefs and way of life
pull (a few) strings	use your influence in order to get sth you want or to help someone, esp when this is unfair
red tape	documents, rules and processes that cause delays
take the law into you own hand	punish someone in your own way without involving the police or the courts, often by doing sthIllegal
the powers that be	the people who control a situation
throw the book at sb	punish someone very severely
under sb's thumb	completely controlled by someone else