One of sour, two of sweet, three of strong and four of weak, so goes the old adage from the West Indies. This is in reference to the (other) holy trinity of the Caribbean: Rum, Lime, and Sugar. Here, "weak" is in reference to water, or the dilution that can be achieved by icing and shaking a cocktail.
Today, the golden ratio (a good place to start) for a citrus driven cocktail, is (3:)2:1:1 (3pt weak, 2pt strong, 1pt sour, 1pt sweet). Most well balanced citrus drinks are going to look very close to this.
While mathematically similar to standard cocktails, most tropical libations add a layer or two of complexity. This can be achieved through the addition of spice, or by dividing the sweet, sour, or strong components into smaller parts.
While many of the tropicals and exotics have their roots in the Carribean, the majority of classic tropicals were created in California, and elsewhere on the mainland. Carribean drinks like the Daiquiri, Mojito, or the Planters Punch gave inspiration for California Classics like the Mai Tai, Zombie, Jet Pilot, Three Dots and a Dash, or Nui Nui.
In the case of "Strong and Stirred" (or "spirit driven") drinks, we tend to balance sweet with bitter, to bring something special out of the strong component.
Take for example, Trader Vic's Mai Tai:
You'll note that the sweet components of this cocktail are broken down three ways, but they still add up to make 2pt strong, 1pt sour, and 1pt sweet. Mix in the crushed ice and you have approximately 3pt weak.
Or Don Beach's Nui Nui Cocktail:
In this recipe the Orange acts as the body of the drink, and if you're to consider it to be both sweet and sour, you'd have 2pt strong, 3/4pt sour, 3/4pt sweet, and Angostura Bitters (spices).