Steps
First Upload the image .
1. Duplicate the background layer
2.. Add extra canvas space by using the crop tool
3. Add blank layer after step 2
4. Fill the new layer with black
5. Add noise to the layer, Filter - Noise - Add Noise,
for amount put 150% and select Monochromatic.
6. Apply the Gaussian Blur effect, Filter - Blur - Gaussian Blur
2.. Add extra canvas space by using the crop tool
3. Add blank layer after step 2
4. Fill the new layer with black
5. Add noise to the layer, Filter - Noise - Add Noise,
for amount put 150% and select Monochromatic.
6. Apply the Gaussian Blur effect, Filter - Blur - Gaussian Blur
7. Add A Levels Adjustment Layer
8. Click "Use Previous Layer to Create Clipping Mask"
9. Reduce amount of noise and increase Contrast
8. Click "Use Previous Layer to Create Clipping Mask"
9. Reduce amount of noise and increase Contrast
10. Apply the motion blur filter to the noise
11. Re Adjust The black and white sliders in Levels, to get preffered rain setting.
11. Re Adjust The black and white sliders in Levels, to get preffered rain setting.
For more instructions: http://www.photoshopessentials.com/photo-effects/rain/