I started my this quest in May of 2018 when I randomly decided to check the dress shoe section of eBay. It is important to filter your search heavily to prevent the mass of random "Italian made" from cluttering your results and make you miss a good deal.
I personally filter by size with a +1 / -1 range. Brands sometimes have very different lasts, this can really affect the way the shoes feel.
Quick example: My two pairs from Meermin are in size 6.5UK. One, on the Elton last, is a bit too tight while the other, on the Hiro last, is a bit too large.
Considering as well that my Crockett & Jones are on the 341 last, supposedly fitting true to size, are a bit too big and my Carmina, on the Inca last, are a bit tight in the same size...
Well, it can get confusing very quickly and therefore you shouldn't filter down to your exact size.
I also filter by brands, I have no interested in brands retailing under 350€ neither do I have interest in brands I have never heard of.
I'm looking for quality dress shoes here, with a good value even at full price.
The latest way I filter down the results is by condition. You have the choice between New with box, new without box, new with defects and Pre-owned. The most ethical thing to do is, to me, giving a second life to a pair of shoes someone lost its love for.
With my filters, the results already went down from an overwhelming number of 189500 to a more digestible 165. The last thing to do is sorting by newest first and bookmark the search to quickly and regularly check new auctions.