Drawing a glass bottle or vase in 3D was the first drawing lesson I received as a child. You can easily make bottles and vases look 3D with the help of ovals.

Exercise 1: Take a look at the following example of a bottle. The bottle is drawn in four steps. Construct the bottle step by step.
Step 1: Start with the vertical construction line through the center, the axis.
Step 2: Draw ovals of varying widths at different heights. Make sure the ovals are nice round and not pointy.
Step 3: Complete the bottle shape by connecting the ovals..

Exercise 2: try to design your own models of bottles or vases in the same way.

If you want your vase not to be made of glass/transparent, you should erase the axis and the back parts of the ovals. Then you can decorate the outside.
