If your opponent is short (on time), play just as you played earlier in the game. If you are short keep calm, I repeat, don't get flustered. Keep up the same neat writing of the moves, the same methodical examination of variations, but at a quicker rate.
Alexander KotovOnce in a Moscow chess club I saw how two first-category players knocked pieces off the board as they were exchanged, so that the pieces fell onto the floor. It was as if they were playing skittles and not chess!
Alexander KotovAnyone who wishes to learn how to play chess well must make himself or herself thoroughly conversant with the play in positions where the players have castled on opposite sides.
Alexander KotovGo through detailed variations in your own time, think in a general way about the position in the opponent's time and you will soon find that you get into time trouble less often, that your games have more content to them, and that their general standard rises.
Alexander Kotov