- Saggy bum - try wearing inside-out, and pin the back seam until it looks better, then re-sew.
- Reduce bodylength - raise a gusset crotch (may need to cut a new gusset)
- Underarm wrinkles - use a broader shoulder dart next time.
Not having a bust to work with myself, these instructions are necessarily poor. The darts and gussets should be curved, not straight. You need to experiment with a french curve. Just remember that the dart edges must be the same length, and the side seams must eventually be the same length.
Darts are triangular pieces, removed from a garment, to create additional shaping.
For instance, if you have a large bust, your bodylength along your side will be much shorter than the length measured over your bust.
- Draft the four-panel pattern as if you have no bust so the side seams will match. (Using this in the two or one panel pattern would result in a long seam around the body, so a gusset would be better, see next.)
- Cut horizontally at your bust's widest point and spread the pattern pieces by the difference between the side-length and bust-length, then draw an hour-glass shape, wide as the front of your bust as its midpoint.
- The sides of the hour-glass should be sewn together, top to bottom, putting a broad 'cup' into the front of the suit, and then the side-seams sewn together as normal.
Gussets are pieces added to a garment, also to create additional shaping.
A similar line of reasoning to making a dart: slash the pattern from centre front to side, and insert a losenge-shaped piece as tall as the side-length vs bust-length difference and as wide as the front of your bust, which tapers to nothing when it reaches the end of the slash.
- Cuffs - cut rectangles as long as the cuff you want to finish, and twice as wide. Sew short edges right sides together. Turn half outwards and sew the two long edges wrong sides together. Match the nap of the sleeve/leg and the cuff, and sew the edges right sides together.
- Cuffs - Alternatively, fold the edge under and sew with three-stage zig-zag. Stretch while sewing. Easier, and the seam won't dig into your wrist.