First take a rectangle (ratio 3:2 approx.). Now take 3point ellipse tool. Drag it from the bottom-left node of rectangle to bottom-right node. Press shift while dragging to make it a perfect circle.
Now select both shapes and weld them
Now make a copy of the glass shape. I have colored the outline of one of the glasses red. It will be easier to explain.
step 1- select black glass then red glass.
step 2- click trim.
Click the bottom curve of the glass and push it up as shown in figure.
Now fill the glass with orange color and its bottom with light grey as shown below. Select them both, right click the "no fill" button. It removes the outline.
We will use trim and intersect commands to add more effect to the bottom of the glass. It is similar to step 2 and step 3.
Draw 2 rectangles and a square as shown. Rotate the square at 30.2 degree. Trim the yellow rectangle with white curve.
Fill the shapes with colors and don't forget to remove the outlines.
Add transparency to the shapes.
Draw two rectangles, fill them with white color and remove the outlines.
Place one rectangle at top of the glass.
Draw two more rectangles with rounded edges.
How to draw rectangles with rounded edges-
1.Draw a rectangle.
2.Select shape tool by pressing F10.
3.With shape tool drag the nodes of the rectangle.
Add a rectangle trim it to make it look like the shape shown in the figure.
Press Shift+ Page down three times to place it behind the rounded rectangles.
Draw a straw fill it with red color.
Copy the rounded rectangle.
Fill it with orange color.
Place it on the right side of the glass.
Draw a circle.
Fill it with white color.
Now add shadows and background.
If you have any problems concerning the tutorial I am always here to help.