Every Thursday around lunch, I open up Estatesales.net and browse the sales for the upcoming weekend. There's typically a dozen or two. I open each one in a new tab, and scroll down through what's typically 100-300 photos per sale. Very quick skim, stopping if I see anything interesting.
I then paste links to specific photos into item-specific category threads in a local makerspace chat: Sewing machines/other fabric stuff, Typewriters/addingmachines/cashregisters/calculators, CRT TVs/VCRs/related, Computers/videogames/peripherals, Tools, Cameras/film/telescopes/projectors/optics, Radio/stereo/DJ/vinyl records, Landline phones. So basically I've done the horizontal browse and sorted it into vertical categories, and anyone who follows those threads for stuff they're interested in, can go to the sale and nab the stuff.
But crucially, estate sales have _everything_, and if the sale folks have reorganized the house, badger them into telling you where the accessories went. If they already threw out valuable cables or something, give 'em hell for it and refuse the purchase, and they'll be more mindful next time.
If you're looking for something specific, show up on the first day. But personally, I just want to keep it from being landfilled, so I show up near the end of the last day. Offer fifty bucks for all the VHS tapes in the house, they'll take it. I got about 3500 floppy disks this way -- other shoppers ended up helping bucket-brigade them to my car as the clerk was closing up shop.