Start from a basic block with darts and 8 to 10cm wearing ease at bust.
Draw the waistband lines: one is approx 2cm below the waist, one is 4 to 6cm above it. They are straight on back, and slightly curved on front. The upper line is more curved and ends at underbust in center front.
Change front waist dart so that it is 3cm wide from waist to underbust, then shaped as a rocket to bust point.