One of the standard pieces of advice offered to would-be, and not so would-be writers is 'Use your five senses.' This is often closely followed by the reminder not to forget the often neglected sense of smell.
So we all do it. Describe how he/she/it smelled. Historical writers seem to take particular delight in the nastier end of the smell spectrum, describing exactly how that Medieval/Georgian/Victorian street reeks - and with what. As I read a lot while eating, it's actually something I could do without. Or maybe I'm reading the wrong books? I do find recipe books particularly appropriate over lunch - and strangely, the people who might be expected to extol one of the most noticeable and enticing aspects of their creations rarely do. They clearly haven't been reading those how to write tips. Or maybe they are wiser than the rest of us in understanding that smell is in the nose of the beholder? After all, how do you describe a smell? You can describe what makes the smell ...
At the moment all the jasmine bushes in my garden are in flower. I have a lot, as it grows like weeds. The scent is wonderful. But wonderful how? If pushed I would probably say it was a soapy sort of smell. But then, what kind of soap - certainly not carbolic.
Smell, it seems to me, is a personal thing. That's my profound thought for the day. Perhaps all a writer can do is describe what creates the smell and leave it up to the reader to imagine.
Of course, that's the deepest secret of reading a book - everything can look, sound, taste, feel and smell exactly how the reader wants it to. How the reader imagines it ...
Actually - I'm not sure that smell is the most overlooked sense. How often do you read or write about how something tastes? Should there be more of it?
I shall go away and ponder that in the garden, within sniffing distance of the jasmine.