Possible Clues:

• There's a tendency for art to turn to it, and that's flat, by the sound of it
• Blue eyes or blond hair
• Just a trace flat, by the sound of it
• Quality in setting up cunning appeal
• Characteristic to be found in the extra itinerary
• Distinguishing feature of bird artist captured
• Disloyal person with no alternative characteristic
• One may be expressed by a gene
• Eye color, for instance
• Curly hair, say