In Go, the Japanese term yose signifies the endgame, the stage when it is already clear whether most groups are dead or alive, and the players make final adjustments to their (and their opponents) territories. In professional games, which are usually very close, this is the stage where winning or losing is determined, sometimes by reducing the opponents territory just by one point.
More than in most stages therefore, Sente (roughly: initiative) and Gote (the opposite) can decide the fate of the game. In yose, the following principles are of utmost importance, maybve more so than in the rest of the game:
Always play the largest move (i.e. most urgent move) first.
Don't reply automatically, but rather look if replying now bars you from a more interesting (worthwhile) move. Be ready to accept some losses to achieve greater gain.
Keep sente. If you are in gote, tenuki to get sente.
Try to get the last possible worthwhile move(tedomari) in most positions.
Finally: Calculate the value of each possible move and position to find the highest gain.The last bit is the hardest, and supposedly takes years to perfect.
For more see Sensei's library on endgame strategies:
http://senseis.xmp.net/?BasicEndgameTheory