This took a little thought I've been using knives so long, I just know it's right when I see it.
A knife has to work as a package so form follows function. At the same time no ugly knives need apply.
Blade length. It doesn't matter closed length is what I look for in an every day knife. It has to fit comfortably in my pocket.
Blade shape. Is always a consideration but I have a variety of shapes I like. It will depend on what the knife is used for.
Blade material. I can be a bit picky about that. I like carbon steel but I really like the newer stainless steels.
Handle material. As long as it's comfortable I like a lot of materials from synthetic to bone but stacked leather is a no go. No finger groves, they limit how you can use the knife.
Lock type isn't relevant, I prefer to rely on safe handling techniques. If I need a lock I'll reach for a fixed blade. So that rules out thumb studs, holes in the blade, assisted, flippers, etc.
I won't look at a black blade.