IDIOMS

pick up on

(transitive, idiomatic) To adopt a practice in which others already engage.

Example: 1882, Charlotte M. Yonge, Magnum Bonum; or, Mother Carey's Brood, ch. 18:
  "Remember, I know more about it than only what you picked up on that morning."
1980, Norman Spinrad, The Mind Game, p. 22:
  No wonder I didn't pick up on what was happening.
1999 Dec. 12, Andrew Goldstein, "The Victims: Never Again," Time:
  Why didn't the police or the school pick up on the killers' warning signs?
2011 May 11, Arthur S. Brisbane, "The Other Torture Debate," New York Times (retrieved 24 May 2011):
  Readers and bloggers alertly picked up on the nuances of language, and what some called the inconsistencies.
2009 Oct. 31, Neil Harman, "Caroline Wozniacki reaches semi-finals", Times Online (UK) (retrieved 24 May 2011):
  Andy Murray has landed in Valencia for next week’s ATP tournament to pick up on his interrupted year, six weeks after the Davis Cup tie against Poland when he played three times in successive days and exacerbated the damage to his left wrist.
2004 Sep. 16, Patrick Saunders, "Eye on the Jaguars," Denver Post, p. D10:
  "What you've got to do is, you've got to study the guy and try to pick up on his techniques, try to pick up what he's real good at."
2010 June 30, Justin Bergman, "China's TV Dating Shows: For Love or Money?," Time:
  China was slow to pick up on the reality-TV trend.