Example of bottle design as shared on reddit. 

Here is a cad file for reference:
Old SW – https://drive.google.com/open?id=1R8z7RZoSUINiMgdB2qVzfLGUpqmiGc5o

New SW- https://drive.google.com/open?id=1xGoChie5GolTDkciPuKJ5oy4DgbstrV8

My other packaging work. http://joshgoreworks.com/portfolio/packaging-design/

You should lookup SPI neck finish thread standards, although others bring up standard thread creation tools it is critical on bottle threads that they follow standards so they work with standard closures. Solidworks now has SPI neck finishes as options with their cosmetic thread but when I did packaging here is what I did.

Reference this PDF, or another similar SPI guideline http://www.seaquistclosures.com/@SCWebsite2/Include/technical_manual_14nov2008.pdf

There are 5 primary dimensions for neck finishes on bottles, although others exist. T, E, I, S, H

  1. Create a plane at S
  2. Create a sketch on S plane with T diameter
  3. Create helix including pitch.
  4. Create plane perpendicular to endpoint of helix. and insert thread profile with the upper edge where S meets E
  5. Sweep thread profile along helix.
  6. Insert plane perpendicular to thread profile plane and draw a radius to sweep thread profile(do not just filet it, this is not a proper thread lead in, see specs for proper radius)
  7. Then detail the remaining stuff and shell the container.