In this tutorial we will model a basic plastic shampoo bottle. It can be later used to obtain more complex recipients, such as a liquid soap dispenser.
Let's start with a Box with the following properties: Length: 70, Width: 115, Height: 250, 2 Width Segs and 5 Height Segs.
Convert the Box to an Editable Polygon then go into Vertex subobject mode. Select the bottom 3 rows of vertices and scale them down a bit in the Front View.