Depends on a couple things. Easiest is if it is a pattern that allows you to add blocks, then add an additional row to the bottom. If not, then look at borders. If the pattern allows, you can add a wide color border to just the top and the bottom and then a regular border (or 2) around the whole quilt. Or make a complete inner border but make the bottom and top wider than the sides and then a regular outer border. My suggestion is to lay the various versions out on a bed and leave if for the day. Every time you walk into the room, register your reaction to the look of it. The one you prefer will make itself very clear.