I would start this project by getting together an image board of existing bottles, logos and other imagery linked to scents, smells, plants, ingredients etc. Also tv adverts and posters that advertise fragrances. Once you have them all down in a sketchbook look for similarities. If they all have something in common think about why? Can you change that something to make yours stand out? One of my lecturers said to start by thinking as ridiculous as you can. How crazy can a perfume brand/bottle be before it stops being a perfume brand/bottle? That's a good place to start as you can then change things to make it more realistic if you have to, rather than the other way round.
Hopefully that's a starting point you could use. Good luck!