Trim, without the pain

Trim is the fussiest tool in the shop, and it gates the game's rarest achievement: only 1.5% of players have used 50 metres on one dress. The trick is treating trim like real trim: short lengths, lots of pins, and patience around curves.

Technique, from players who fought it

/Work in short lengths. Place a pin every few inches and continue; the game does not make you re-click, and more pins let trim follow the dress's curves and folds.
/Hover the red pins to highlight a length in yellow. Click a highlighted section to select it, right-click to delete back one pin at a time, left-click a pin to continue from there.
/Upside-down trim means you dragged the wrong way. Drag the opposite direction and it flips.
/Clipping a lot? Use the adjustment buttons to tilt the trim up a little. Holding raise or lower moves faster than tapping.
/Cuffs are the hardest spot. Zoom in with Z, hold the scroll wheel to orbit the camera around the cuff, and work slowly.
/If trim stops cooperating at a fold, go back to where it sat nicely, pin, and continue. Trim cannot magic its way across a seam, same as real life.
/Sleeves in the way? Take them off while you detail. Dress parts are optional until delivery.
/Trim sews itself on when you finish the dress. Check the fabric tab to preview it without pins.

Trim and Proper, the easy way

Do not track scraps. Buy 50 metres of one trim and spend the whole roll on a single dress, anywhere it fits. There is no beauty bonus for this one, so save your creativity for paying clients. Full numbers on the achievement page.