1. Find or open glass photo, I used this one -> Lemonade Glass
2. Resize it, in my opinion it's too big.
3. Find photo of ocean, this one is great.
4. Copy and paste it to our glass document.
5. If it's much smaller than glass, resize glass once again.
6. Reduce ocean layer's Opacity to about 30%, you can see glass now.
7. Choose Polygonal Lasso Tool.
8. On ocean's layer make a selection like this:
9. Press Ctrl+Shift+I to select inverse, then Delete to delete it.
10. Press Ctrl+D to deselect.
11. Choose Pen Tool.
12. Try to get selection like this (Click and drag to get more curvy shape):
13. Go to Paths tab, right click on your new path and click Make Selection, then OK.
14. Go back to Layers tab, choose ocean's layer and press Delete to delete selection, delete also "Shape 1" layer.
15. I should correct upper part of the glass. I'll use Eraser Tool.
16. Set ocean's layer Opacity to 50%, and set Layer Mode to Overlay.
17. Repeat steps 11-13 to get selection like this:
18. Select ocean's layer and apply Ocean Ripple filter (Filter -> Disort -> Ocean Ripple) with these settings:
19. Done :)
More Tutorials: 
