Take in a Dress at the Waist

This is quite straightforward. You will need some dressmaking pins and a mirror might be helpful (or a friend).

Steps

Put the dress on inside out.
Put your hands on either side of the waist and pinch equally how much you want to take in.
Put your first pin where the most fabric needs to be taken in.
Pin up and down the side seam until you have a good fit.
Remove the dress and tack along the pin line.
Put the dress back on - the right way round this time, to check that you have the fit you want - adjust if it's wrong.
Machine sew along the line of tacking stitches.
Remove the tacking stitches.
Try the dress on again.
Cut away the excess fabric, leaving about {{safesubst:#invoke:convert|convert}}.
Press the seam open to get a good finish.
Now you're done!

When tacking, make sure that the new seam tapers away to nothing at each end of the alteration.
Be careful not to stab yourself with the pins when you're removing the dress, if you do stab yourself make sure to put antiseptic on it and place cotton wool over it, and try not to get it on the dress.