Your character would only notice what you would notice.
Do you notice the color of your hair on an average day? Do you tell yourself in your head that Lisa is your sister? Is it possible to consciously notice when you’re unconsciously looking at a cloud? Would you know at one moment that the next five minutes will bring you a promotion?
Your character, going about his average day, wouldn’t notice certain things that are commonplace or actions that are unconsciously done. Don’t write what your character wouldn’t consciously notice to himself.
Jennifer wouldn’t notice her own hair because she sees it everyday, so don’t write how Jennifer tossed her long, silky blonde tresses out of her face. (She probably wouldn’t even consciously realize she was doing it—do you consciously note every time you brush the hair out of your eyes? Do you consciously note the color of your hair every time you brush it out of your eyes?)
Dave wouldn’t tell himself, “That’s my sister Milly crossing the street toward me.” He’d think, “That’s Milly crossing the street. I wonder what’s up?”
Amy wouldn’t even be aware what she was staring at if her mind is wandering, focused on something else, so don’t write about her gazing unseeing at a shop window.
Sara would only think she was on a nice early morning run, she wouldn’t see anything unusual, so don’t write that she didn’t see the glowing eyes watching her from the darkness under a bush. Of course she didn’t see it—so don’t write what she doesn’t see.
Be careful about narrative and description—remember that you’re in the character’s head.