Take good measure of the clothes
Observe the clothes carefully before you choose to alter it. Place the cloth ( need alteration ) on a level surface, then put your dress of current size on top of it, to mark dimensions. Highlight the new stitching line where you will be making the alter seams. You can mark this by the help of tailor’s chalk.
Alter and try it
Fold the altered seam and crease it with your hand. Sew loosely (baste) the seam with a thread and needle. Be careful and try your dress to check if it fits correctly on you. If you still require more alteration, then take them off. Make the adjustments and try it on again until it is your exact size.
Sew using a sewing machine
Attach by stitches the new seam that you altered with a sewing machine. Cut off the extra material from either side of the seam. This can be done with the help of a pair of scissors. Make sure to iron the new seams to keep the cloth flat. On the other hand, you can also perform this activity with the help of a friend. Tell your friend to mark the areas to be altered for you, while you are wearing the clothes. This can be a more accurate way to get a perfect fit.