There's an out-of-print Clue variant called Clue Master Detective, differing from the regular version mostly by offering more possibilities {10 suspects, 8 weapons, 12 rooms}. Also, certain squares of an enlarged board allow when passed over one to snoop a card from another's hand. (There is a slight procedural difference when making suggestions which isn't necessarily necessary.)

Generally, the strategy is don't be the Candlestick and wander the hallways.