I’ve designed a few fragrance bottles. Each one has been a little different. A lot of the time you have free reign when designing. Sometimes they give you a sample of the scent and some words that they feel describe it. Other times they have already done a photo shoot and you can pick up forms from some of the imagery. I find that the price point and cost of goods will also drive the design quite a bit (this is sad i know, i try to stay away from thinking like this). Molding with glass is so much different than with plastic. Often how you treat the glass will drive tooling costs significantly.