this is what I look for in a folding knife:
blade steel: I prefer something like 154CM, 14C28N, N690, VG10, NitroV. I like these bc of their ease of sharpening, corrosion resistance, and they have decent edge retention and toughness
or I also like M390, S90V, CPM20CV, CPM154, S35VN. S30V. I like these bc of their edge retention and toughness, corrosion resistance, although these are more difficult to sharpen
opening action: I prefer a flipper tab. I don't like the new button locks or axis locks bc the opening isn't as snappy as a liner lock or frame lock. I don't like opening with a thumb flick or finger flick bc usually that means the detent isn't that strong and I just don't like opening it that way
locking mechanism: I prefer liner lock or frame lock. I like it when the frame lock has an inlay that covers the lock bc you can't fail the opening by having your fingers on the lock. but some don't have a inlay and they work fine. I have a couple that I have to be careful how I hold it when opening
blade shape: drop point, spear point, clip point, tanto, sheepsfoot. I like these bc they are a useful and functional shape for EDC
blade size: 3.25"-3.75" is ideal for me
handle material: titanium, G10, Micarta, carbon fiber. really doesn't matter too much if it's done right
I really like a snappy opening action with a manual flipper. detent on the strong side, but not too strong, enough so I cannot fail the opening even if I try but not too much so it takes more effort to open, I like it in this sweet spot. I like ceramic bearing for a drop shut closing, although ZT has steel KVT bearing system that works really well
pocket clip: one that is easy to draw and easy to put back in pocket and big enough to sit in a thicker pocket like jeans or thicker pants
lanyard : I like the option of using a lanyard, although it's not a deal breaker to me
that's all I can think of right now. I'll update if I think of anything else