1. Brush the decoupage medium on the frontside of a leaf; then place the leaf wet side down on the backside of the plate. Brush a second coat of decoupage medium over the leaf. Repeat this process to adhere several leaves.
2. Tear tissue papers into assorted sizes and shapes. Brush decoupage medium on one side of a tissue-paper piece. For contrast, place darker paper behind lighter leaves and lighter paper behind darker leaves. Lay the wet side of the paper on the leaves. Smooth out any wrinkles with your fingertips. Brush more medium over the paper to saturate. Repeat to cover the entire back of the plate with tissue paper. Let the decoupage medium dry for 12 to 24 hours.
3. Use scissors to carefully trim any tissue paper that extends beyond the rim of the plate. Brush gold-leaf adhesive around the plate rim. Let the adhesive dry for 30 minutes, then apply a second coat.
4. Allow the adhesive to dry for another 30 minutes, then follow the manufacturer's instructions to apply gold leaf around the rim of the plate. Apply a coat of sealer over the finished leafing. To clean the glass, gently wipe the surface with a soft, damp cloth.