Arranging the tiles accordingly is a vital step. It can be tempting to separate the tiles in a manner that shows how close the tiles are to forming a complete hand. But this is a counter-intuitive approach as it could give the opponent vital clues like if they are about to be defeated.
Regrouping the tiles into Kongs, Pungs, and Chows lets another player know that a complete hand is about to be formed by their opponent hence they up their game to prevent a potential win. However, the same scheme can be used to send the wrong signals to the rival.