As a kid I was always pretty good at image match games, the one’s in which you just revealed a picture and must remember under which closed panel, or back faced card, you may have seen that same image before. This I attribute to a pretty good short term memory. My long term memory is not as good, likely because I’m somewhat of an introvert. I don’t often talk about past events, nor am I much of a personal storyteller, that would allow for reinforcement of memories. As such I do not often set events well as a mental video in long term memory by continually reinforcing the event by oral story telling.
So how do I reinforce my recognition for quality snuff bottles, understand the nuances of old vs modern, realize artistic merit regardless of age, and sense that a snuff bottle I’m presently looking at is one I may have observed before? Well as we have all said here, this is best done by looking at a lot of snuff bottles, handling them when feasible, and build an extensive reference library that is easily accessible. I spend a lot of my free time reviewing old auction catalogs, viewing present auction sites online, and acquiring books that document old and present snuff bottle collections. For me the review of books and catalogs is often done in the half hour or hour in bed at night before I fall asleep. Awe, the dreaming of snuff bottles!

Though, actually such dreams have never occurred.

This practice I feel does help with retention of image recognition.
Below is a color plate from Sotheby’s “Fine and Important Chinese Snuff Bottles from the Collection of Bob C. Stevens, Part II, 1982”. The accompanying snuff bottles were acquired from different auction house locations within the last few years. Though at the time I did not know where I had seen each bottle, I did sense that I had seen the bottle before and understood their quality even though I could not see or hold them in person. In each case, the bottles did not generate much interest at auction, and I feel were overlook. As a result, I was able to purchase these two bottles for about the same price they sold for in 1982.
So, with training of the eye, you can get LUCKY.
Charll