The larger amount of blues and reds.
Females, as stated previously, are usually much more plain. Depending on the strain they are typically a peach color with black/grey blocthing.
Some strains may have more or less blotching or different base colors (white, gold). In these cases females are simply more muted in color and finnage than their male counterparts.
Kudos to you for picking up one that doesn't look hormoned.