Cutting celery is a simple process. First, trim the bottom of the celery. You can discard the stringy pieces at the bottom or save them for adding to soups and stocks later on. Next, you should trim away any pieces that look wilted or bruised. To obtain chopped celery, you need to cut the celery into smaller pieces of about 1/2-inch in thickness. Afterward, you can chop them to your desired size and shape.