Shoulders first, and half the other problems disappear
Shoulders first
The seam should sit at the edge of the shoulder bone. Wrong here and every drag line below it is a symptom rather than a fault.
Then the length
Sleeve and body length, which are simple and independent. Do these before touching any shaping.
Shaping last
Waist and bust adjustments, which depend on everything above being correct. Doing them first means doing them twice.
