There a well known, long-established patterns for beating Pac-Man's mazes, up until the ninth Key, as Buckner & Garcia sang. Still, Pac's adversaries exhibit behaviour that, if not exactly tactical, is still complex.
Chad Birch, a researcher from Calgary, writes Game Internals, which "aims to spread knowledge of interesting game mechanics beyond the game-specific enthusiast communities." The breakdowns are comprehensive and written even for those with no understanding of the game.
So it's intriguing to read up on the three phases of ghost behaviour, the durations of each, the areas of the screen to which they will run when in "scatter" mode (pictured), and why, exactly you're able to play chicken with Pinky and Inky fake them into turning away from you.
I'm not saying it'll make you into a Pac-Man champion, but it's a great weekend read and sheds a lot of light on a game that defined its time and, in its own way, was ahead of it.
Understanding Pac-Man Ghost Behavior [Game Internals]