Creating reflection on liquid in a glass
Start by opening an image of a liquid in a glass.
Insert another image that will be used as reflection map.
Duplicate and hide the layer. Select the duplicate layer and Press Ctrl+T. Right Click and select Warp. Adjust the nodes to get the shape as shown.
Select eraser tool with big radius and soft brush settings. Erase the portion out of the glass.
Also erase hard edges to create a smooth blend.
Repeat all the steps mentioned above for the lower half of the glass. the only difference is the for lower half portion instead of using a soft brush setting for eraser we used a hard brush setting.
a selection of a portion of reflection map layer. Copy and paste in a new layer.
Change the layer mode to "Soft Light".
Similarly create reflection on the bottom of glass. From ""select Liquify. Distort the texture using forward warp tool.
Similarly create more reflections on other parts of glass.