Drag an instance of the CC Particle World particle effect onto one of the silhouette solids to create a basic particle effect. Set the particle type to Textured Faded Disc, then select the flower layer as the texture layer. Experiment with the physics properties and set the Particle Birth Rate at a reasonable number; we opted for 200.
View a RAM preview by pressing 0 on your keypad, and sit back and wait for a while as After Effects renders the Particle Effect.
You may see an improved performance by pre-composing the Particle Effect layer once you’ve added the CC Particle World Effect.
Finally, colour correct the dancer by adding a levels effect (Effect > Color Correction > Levels) and drag the white point to the left of the graph to create a brighter image over the dancer. Now add an additional black solid with a heavy feather over the bottom third of the comp to disguise the fringing.