A beer that is too light in color (as per style guidelines) does not have enough specialty malts added. Beers that are too dark have too much specialty malts, incorrect malts or caramelized during the boil. If you are not entering a competition and like the flavor of your beer, don't change a thing.
Follow the recipe according to the style guidelines to achieve the proper color; ie. substituting Caramel-60 for Caramel-120 won't work. When adding extract to the boil, remove the pot from the heat to avoid caramelizing the wort and avoid a darker than expected beer.
Colors may vary with different monitors and printers; use this as a general reference for beer color.