Things You'll Need
Jackets are useful to wear when it's cold outside but sometimes the waist can be too large for various reasons, such as losing weight or getting a hand-me-down jacket from a family member. Making the waist smaller is a process that should only be attempted if you understand the process of tailoring a jacket. Otherwise, you can ruin your jacket. The steps themselves are rather simple for people who have altered a piece of clothing before.
Turn your jacket inside out, put it on and close it. Hand your helper tailoring pins and have them find the seams of your jacket.
Tell your helper to pin the cloth along the seams to shorten the length of the waist. Get them to stop once the waist is the size you want. Remove the jacket.
Place your jacket on a flat surface and spread it out evenly and flat. Thread your needle and place it at the bottom needle at one of your side seams.
Sew upwards from that needle to shorten the seam. Keep sewing until you get to the last pin. Tie the thread ends together to hold your new seam and remove your pins.
Press the seams of your jacket flat and reverse it so the right side is facing out. Put on the jacket and try it on to check your adjustment. Remove your stitches and resew if necessary.