Imitate this water picture

I forgot to mention that it helps to add a slight blur after you draw a black shape for the water drop. Filter > Blur > Gaussian Blur at a low amount around 0.8, to soften the edges of the water drop.

Fill a layer with the blue background color.

On a new layer above the blue layer, draw a black shape for the water drop.

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Lower the Fill to zero percent.

Add Drop Shadow, Inner Shadow, and Bevel & Emboss layer styles using the settings below. That should get you close to what you want.

Here is not the best space for tutorials. I will try with brief instructions:

• Create shape using any drawing or painting tool.
• Lower Fill opacity to 0. There is Fill slider below Opacity in the Layers panel and also in the Layer Style dialogue. This will set opacity for shape to 0 or invisible but you can apply and see layer effects from Layer Style dialogue.
• Use Bevel and Emboss, probably Inner Shadow and Shadow to create final effect.
• I haven't tried to recreate but you may need to work on two layers for final effect. If you can't do something or it seems you can not do using Layer Style then use painting tools and mask as needed on separate layer.