Next, move the vertices according to following image. Try your best to match the vertices as close as possible to the reference image (Fig.11).
Step 3: Modeling the top part
Select the edges of bottle and extrude them, similar to the following images (Fig.12 - Fig.14)
Modeling the Cap and Treads
We start off by making a poly cylinder with the following parameters:
Subdivision Axis: 20
Subdivision Height: 1
Subdivision Caps: 1
Select the lower vertices and scale them towards the outside a bit, then delete the lower cap. Select the lower border and extrude it towards the inside. Use the following image as a guide (Fig.15).
Make a "poly Pipe" and position it under the cap. At this point, you're almost done with the cap (Fig.16).
Now, make a triangular tread and align it with a cap door. You can use Vertex snap tools by holding "V" to make sure the tread is aligned properly. Make sure the pivot is exactly in the center of cap. Press "E" to switch to rotate mode then "Duplicate" it to make 20 treads (Fig.17).