Each level of Scouting provides girls with new opportunities and challenges. Have the girls act out the next level by performing a skit. A popular Daisy skit involves "baking brownies." The leader recites the list of qualities that make a good Brownie while the Daisy Scouts hide in a cardboard oven. At the end of the skit, all of the Scouts pop out of the oven; they have become perfectly baked Brownies. Older scouts can perform skits based on new activities they are excited about participating in or skills they hope to learn.
While a bridging ceremony encourages girls to look to the future, it also asks them to honor the past. Have each girl select a favorite memory. Perhaps it was that camping trip with the fire that wouldn't start or the rather unglamorous items they created while attempting to earn the Sew Glam interest project patch. Encourage the girls to organize their memories by date. At the ceremony, have the girls stand and share their memories. When the memories are in chronological order, the girls will see how much they've grown.
Everyone wants to be remembered for something. Have the leaders come up with awards for each of the girls. Perhaps the helpful girl can win the Helpful Hand award and the girl who wore espadrilles to survival camp can receive the Best Dressed award. The leaders can present the girls with trophies or can come up with a unique award to go with each title. For example, the Best Dressed award might be an old tennis shoe.
If you want to create an emotional ceremony, divide the girls into their small patrol groups and have them write their own songs and poems about what the troop has meant to them. If the girls feel they need a rehearsal, by all means, have one. If the girls are willing to present their material without a group rehearsal, encourage them to keep their work a secret that is only revealed during the ceremony.