Here, I dropped a horizontal version of one of BB's Christmas stripes on the dress, so you can better see the dart placement: 

Another thing is different material zones. This dress has zones called Sleeves, Bodice, Collar, Waistband, and Skirt. Having multiple mat zones allows one to use different fabrics for different portions of the dress, such as having a contrasting collar and waistband. 

(The skirt is morphed shorter here than the original model, so the UVs aren't exactly the same ratio. Having the saame ratio of UVs on different mat zones is important for prints, as well, although with very busy prints it's easir to fudge.)

花 | 美 | 花美 | 花火 
...It's a pun.