Tile efficiency
Tile efficiency is a process of hand development, where a player seeks to make maximized use of either draws and/or discards to attain or even complete the hand as fast as possible. It rests on the limited number of draws, discards, and even hands, that players can use to win or even try to win. Tile sources come from the opening hand, wall draws, and other players. It is up to the player to make the best decision on tile draws and discards.
Unlike Poker or many other card games, the hand value is not a determinant towards winning. Instead, it is a matter of who develops a winning hand first.
Categorizing tiles
Isolated
Taatsu
Yaku
When building hands, yaku are certainly considered as they are a criteria for valid hands as well as added value to the hand. So, almost always, players have yaku in mind.
In other cases, players may end up simply having tenpai in mind, especially as the hand nears the later discards. This is of particular concern for the current dealer, who may have an interest in retaining the position and repeat the hand.