Start by tracing your contoured block (=dress pattern with darts and zero wearing ease).
You can learn our method for drafting perfectly made to measure basic blocks (contoured ones, and the ones with wearing ease) and for fitting them in our basic blocks course/module 1.

Lengthen to desired measurement, then draw the slash line that separates bodice and skirt:

• on back it is the waistline
• on front, it’s a slanted line from waist on side seam to center front 4 to 6cm below waist.

Draw also the new neckline, which has a bit of a armhole shape, approx 1cm inwards from basic armhole and stops 5 to 6cm above armpit level.
We suggest at least 6cm coverage above bust level on front, and a gentle U shape on back.

On front, widen shoulder dart by 1cm at the new neckline (pink line) the draw a slash line from but point to neckline, 2 to 3cm sideways, for manipulating the princess line in a more flattering position.

Cut through the waist slash line to separate bodice and skirt pieces.

Focus on back bodice:

• measure back neckline (as red double arrow)
• get a basic sleeve and measure its back width about 5 to 6cm above armpit level (matching to back neckline level).

Draw a rectangular piece that is twice the width of your final piece: let’s assume the bardot collar will be 10 to 12cm wide, so draw a vertical line 24cm long in the middle of a sheet. This is collar center.
Then square from the uppermost edge towards both direction, and mark the neckline measurement (red arrow) then back sleeve width (blue arrow) in both direction, and add about 20cm to each end for the bow. You can increase or decrease this last measurement depending on how long you want the tails to be.

Repeat the same process for front, as the measurements will be different. Mark the single measurements with notches to have a reference for sewing.