Have ever felt like you were in between sizes? One size feels too tight and the next size up is so loose that it looks like you are wearing your mother’s clothes. I have already shared about buying the larger size and having it altered to fit, (see https://frugalfish.org/2013/02/27/my-new-winter-coat/).
This tip is for the item you purchased in the smaller size, or an item that has shrunk in the wash.
Pin the seams together and sew a line next to the zigzag stitching.
Rip out the original seam and you have given yourself some breathing room!