Bordering lace is typically decorated around the entire perimeter of the gingerbread shape (e.g., heart) or as a finishing touch on one, usually the bottom, edge. There are truly countless variations. What you should always consider, however, is whether the lace border in a specific case serves only as a simple elegant finish harmonizing with the pattern and decoration technique used, or whether it will be the dominant decorative element. Then you can choose a greater width and richer patterning.