Lace always adds an elegant touch, taking something simple and even a bit casual and turning it into something more formal. The easiest way to enhance a top or gown is with lace appliques. For this, you will need a garment you wish to decorate--sometime with simple lines and a solid colour works best. There are numerous clothing patterns for simple yet elegant garments if you wish to sew your base garment. Otherwise, when buying a base garment, consider where you would add lace.
Cut out flowers, flower groupings, etc., from the lace fabric. If you only want a few appliques, a yard of lace fabric will suffice. If you intend to cover the garment in appliques, you may require more yardage. Note: If you are using store-bought lace appliques, skip down to the section on attaching the applique.
Trim the edge of your cut-out carefully. Then set the edge with Fray Check (or Fray Block, etc.). Let dry. This finishes a simple lace applique.
(Optional) Cut out a piece of fabric to back your lace applique. This fabric can be an exact match to your dress or a contrasting (yet complementary) colour meant to show through the lace. Cut this piece to match your applique perfectly. Serge the edge of this fabric if you have a serger--a special type of sewing machine that uses multiple cones of thread to create the sort of finished seams you see on store-bought clothing. If you do not have access to a serger, either use Fray Check around the edges, or (if your sewing machine is capable) do a tight rolled hem around the applique. Sew the fabric onto your homemade lace applique.
Pin the appliques where you think they should go. Arrange them on your garment until you like the overall effect. Make sure each applique can lie flat, without bunching up.
Sew on each applique by hand. Note: if using a store-bought applique, it is possible the applique will simply iron on. If so, follow your applique's directions.
(Alternatively) You can make your applique an iron-on by using a fusible bonding web such as Stitch Witchery. Cut out the fusible bonding web to match your applique. Note: iron-on appliques (even those that come that way) will probably require some sewing as they tend to peel off with wear.
(Alternatively, continued) Set your iron's temperature based on the lace (is it cotton lace or acrylic?). With the fusible bonding between the lace applique and the garment, and a pressing cloth over the lace, gently iron on your applique. Let the applique cool before peeling off the pressing cloth. Note: as lace has holes, you should make a test applique with a scrap of fabric to make sure the holes are not so large that the fusible bonding melts through and sticks to the pressing cloth.
(Optional) Spread glitter glue over parts or all of the applique for a glittery sheen. You can use a matching coloured glitter glue or something that will contrast--such as gold or silver. Lay down thin lines and thin layers for a more formal look. Possibly lay a thin line around the edges of flowers. Or fill in the centres. Or lay down a line and then, using your finger (or a toothpick), spread the glue across the petals. Cover some of the flowers or all of them as you prefer.
(Optional) Decorate your applique with beads. Using a beading needle, sew seed beads, rocailles, or bugle beads onto your applique. Just as with the glitter, you decide how much or how little decoration is needed. Use the bugles to create a spray from the centres out onto the petals. Use the seed beads or rocailles for filling in patches. Any bead can be used to line the edges.
(Optional) Add gemstones for sparkle. Gemstones (or rhinestones) fit nicely as a flower's centre. You might add them between flowers to fill in some of the lacy voids. Sew-on and glue-on gemstones come in a variety of colours, but for sheer sparkle, you cannot beat a rhinestone or swarovski crystal bead. (See links below).
Another great place to find lace appliques and fabric for making appliques is at second-hand shops. Often you can find an older formal garment you can cannibalise. Since you are buying the garment with the intention of cutting out pieces of lace, appliques, or even parts of appliques, the garment size does not matter.