Take a step back and check that you are satisfied with the direction your work is heading in. Next, duplicate the blurred layer. Select Edit>Transform>Scale, resize this second splash, rotate and reposition where you think it looks best. Now merge all three of the water splash layers together.
Bring up the Layer Style palette, select Blending Options and ensure the Preview box is ticked. Select Bevel and Emboss with an Inner Bevel style and Technique set to Smooth. Move the Depth and Size sliders (there are no strict settings these have to be on; play around to get something that you like the look of).
Next up, create a new transparent layer and merge this and your splash together. Then select Filter>Artistic>Plastic Wrap and enter the following settings: Highlight set to 20, Detail set to 10 and Smoothness set to 10. These settings are given purely as a good starting point, so play around with them for a bit in order to see which effect you think suits your image the best.
Next, select the splash layer. Hit Image>Adjustments>Levels and start by moving the dark arrow on the slider. This will vary from shape to shape, so play around until you have the desired water result. You will need a lot of these water splashes (examples are included). Drag the finished splash onto your image, setting the layer’s blending mode to Screen. Now begin to build up your composition.
The rain coming from the clouds is created by duplicating the original downpour layer, reducing the size to match your cloud width, rotating and then setting this layer to Hard Light. Move it up to sit below your new cloud layer, then add a colour overlay with a Color blending mode. Use Levels to reduce or increase the rain drops, and change the Opacity value to blend.
Create a new layer, then use the Marquee tool to draw a long rectangular area. Choose the Gradient tool, select rainbow colours and fill the area by dragging the fill downwards (holding the Shift key keeps the fill straight). Apply a Gaussian Blur with a Radius of 15. Use the Warp tool (Edit>Transform>Warp) to bend your rainbow into the shape you want. Set the blending mode to Screen and change the Opacity value as desired.
Now you can begin to add any extra little details, like the fish, bubbles or water droplets on the ground. Also, paint in other highlights and shadows to the girl, including her shadow. Locate the supplied text file with useful links to some of the brushes used, including the black water splashes at the bottom of the image.
On a new layer, create a rectangle using the Marquee tool and fill it with white. Use the Perspective tool (Select>Transform Selection>Perspective) and make a slanted cone shape, then deselect the Marquee tool and add a Motion Blur, with Angle set to -45. Set the layer to Hard Light and reduce the Opacity. Delete areas if necessary.
Next, create a new layer and fill this layer with a sampled colour from the floor. Now set the layer to Overlay and reduce the Opacity to at least 50%, which will give your image an even tone all over. Finally, mask out the edges of your image in order to emphasise the lighting effects.