11. Change this layer mode to Darken and opacity to 30%.

12. Here is the very light reflexion but which brings a small key of realism.

13. Finally I added the filter Filter> Distort > Glass in order to scramble the reflexion a little. It is not really essential, but if one wants to look more closely at the image we’ll see that water disturbs the reflexion.

14. We return to our water drops! For this final effect it is necessary to flatten all the layers of the scene, so make a copy of your file and
choose Layer > Flatten Image. The image is now made of one single layer, we will be able to apply effects to the whole image now. In menu Filter choose Liquify. Click on the Bloat tool in the toolbar on the left of the Liquify window. Setup your brush radius and its density and paint on each drop in order to simulate an effect of diffraction. It is not very easy at the beginning so
do not hesitate to start again as many time as you want.

15. Once that you made all the drops you can also create water trails behind the drops which run along the window. I used a mix of several tools of the Liquify module like Forward Warp or Turbulence. Leave Liquify. Finally we will accentuate the light and dark areas of the drops by painting with the tools Dodge and Burn.

16. So here’s the final result: