For a sweet sixteen an ideal party would be hearts. You could choose a specific color like mine would be pink. The SPECIAL GIRL dresses in a pink dress and everything is pink with pink hearts and ballons and occasional glitter. I should mention that t his party would be a black tie optional party and i would hold it at a hall. It would be a girls matchmade in Heaven. You could do the invitations in harts and have a dias where a limited amount of girls who mean the most to the SPECIAL GIRL sit. In the middle of the dias would be a heart shaped wicker chair kind of like some bride and grooms like to use. You can do a candle ceramony and have all of the candles be pink. If you just use your imagination it can be beautiful. so the theme would be (specific color) hearts ex: Pink and Pink hearts !