Many beginners and even novices, go in for the kill too early. They're pieces are under-developed and they don't have enough material in position to finish their opponent. Worst of all, they continue fighting regardless of the fact that their initial attack has been effectively repelled. This lack of retreat can put to ruin the best of positions. An important skill in the End Game is to know when to retreat and more importantly when not to attack in the first place. In most cases more than one piece should be ready to attack the King if need be. If you're caught with only one your opponent can ambush you. If you've lost your Queen you should shift your priority to trading and capturing pieces so you can increase the range and manuverability of your Rooks. Just keep witling your opponent down until you're ready to finish him or her off.