Drawing a glass with drink inside

Start by opening a new file. Create a ellipse shape using elliptical shape tool.

Using pen tool create a glass shape.
Create another ellipse at the bottom. Use a darker shade of sky blue.
Double click the first ellipse layer to open layer style window and enable stroke. Apply settings as shown.

 

Now apply stroke to the rest of the shapes.
Create a shape to hide the bottom joint.
Now we'll add some drink to the glass. Create an ellipse as shown.
Now create path as shown using pen tool. Basically you'll have to offset the glass shape only.
Double click the layer to open layer style window and enable gradient overlay. Apply settings as shown.
Now apply the same effect to the ellipse layer at the very top of the inner path.
To make our glass look more glassy we'll add a reflection shape to it. Using pen tool create a path as shown. Use white color as fill.
Change color mode of this reflection layer to overlay. Applying overlay color mode will add a see through effect which is perfect for a glass reflection.
Apply a cool gradient to the background.
Your glass is ready with drink inside. Wanna have a sip!