To get extra lives in pacman game, focus on earning points by eating pellets, fruit, and ghosts. You receive an extra life after reaching certain score thresholds, typically at 10,000 points or other intervals depending on the game version. To maximize your score, try to clear the board of all ghosts after eating a power pellet, and aim to collect every piece of fruit that appears. Practice and strategy are key to earning more points and extra lives, allowing you to extend your game play and achieve higher scores.