Now that I've finally gotten the image to load, based on the drawings, which are a bit sketchy, I would say you should have at least 6 pieces making up the torso: front right, front left, front side right, front side left, back right, and back left. This will give you five seams to use for tailoring (center back, two underarm side, two overbust side front). Keep in mind that all seams, except for the center back, are paired, so whatever you do to one, you need to do the same to the matching seam on the other side. Five seams should give you plenty of places to fine-tune the tailoring (again, without being able to see how it is not fitting, it's tough to diagnose); you may wish to look up tutorials on self-drafting a corset pattern, as that is one type of garment that will have the vertical seams you are looking for.
Be sure to accommodate for the difference between your waist measurement and your hip measurement. Many people do not adjust this adequately, and the reason the garment bunches up is because they have not allotted enough material over the hips. This means the garment cannot hang or drape properly, and cannot be pulled down, resulting in excess fabric around the waist/back.
That's the best I can offer!
Pictures and tutorials from my costuming portfolio at Syagria's Cosplay Site!
Star Trek Original Series Uniform!
Original Creation for AB13
Most Recent Con:
PAX East, Anime Boston 2013