When drafting the back piece, you must account for the zipper:
Apply a thin strip of fusible interfacing to the seam allowance where the zip will go. This prevents the fabric from stretching or puckering. BahSeexy_B_n_zip
Drop the outer shoulder point by about 1.5 inches to mimic the natural slope of the body. When drafting the back piece, you must account
Using a zipper foot, sew as close to the teeth as possible. The goal is for the zipper to be completely hidden in the seam once closed. 5. Final Assembly Sew the shoulder seams and side seams. Using a zipper foot, sew as close to the teeth as possible
For visual learners, many creators on YouTube offer detailed "Draft and Cut" tutorials for trendy tops that use these exact principles.
Measure down from the shoulder for your armscye depth and draw a "J" curve.