The first step for any pattern hack is to trace your pattern. You never want to hack using the original for two reasons: first, if it's a printed pattern, you completely lose the original and second, if you cut into the original, you have no frame of reference if you mess up later.
For my project, I printed out the Sweetheart dress and traced the bodice pieces, but made a cut into the sweetheart neckline where the striped pattern changes direction.
Important note: due to respect for the original pattern maker, I will not be showing any full pictures of my pattern pieces, except for the hacks I made directly. This is to ensure that no one can recreate her original design.
Tracing and cutting the bodice went really well. It was easy to match the stripes and soon I was ready to cut the skirt. This is also when I realized the peplum skirt pattern that I had originally intended to use made it near impossible to match the stripes or do the diagonal stretch that the Barbie suit required.
This caused the first of what I'm sure will be many frustrations with this project. I ended up asking my husband for help and eventually when neither of us could figure out how to make the peplum skirt work, I gave up and started watching Downton Abbey.
About 15 minutes later, I realized that I could do an unfolded half circle skirt with a cut down the middle to match the midline seam from the bodice. I traced out the bottom of the bodice and drew an a-line skirt from the sides of the bodice to complete the pattern and cut each half separately from matched stripes. After getting the front bodice and front skirt cut out, it was time to cut out the back of the striped part of the costume, which in comparison was easy-peasy since everything could be cut on the fold.
This ended up being my stopping point for the night, so my next update will pick up on the nude part of the costume.
Oh! And before I forget, the accessories for my costume came last night: white cat eye sunglasses and gold hoop earrings. The total for these was about $15. Thanks, Amazon!