In drawing the patterns for the Rider Vest I started off copying a well-fitting base, keeping the shoulders but relocating the vertical seams to match those of the accompanying basque, merging two side-pieces into one and delineating all non-tailoring design-lines onto the pieces within the process, allowing me to verify these onto cotton before continuing onto the advanced patterns featuring decorative seams and folded layers.
Obviously, the last step took place after alterations were done on the prototype.