Copied and pasted one glass. Changed a few of the water drops on the glass so it didn't look exactly the same as the one I copied. Changed Hue/Saturation to purple. Erased a bit of the shadow to make it match.
step 2 of 5
Changed the Hue/Saturation of the other glasses.
step 3 of 5
Added the beach photo to the background using Overlay mode. The beach photo is my own.
step 4 of 5
Added some color to the liquid inside of the glasses.