Eye color
If you want to gain someone’s trust and come off as someone who actually cares and is interested in what they are saying, memorize their eye color. Just look into their eyes enough that you know their eye color by heart, it can give you the impression that you are actually invested genuinely into that person.
Of course, do not stare deeply into someone’s eyes for a long period of time, just like anything else on this list, staring can get weird fast. Subtly look into their eyes until you know their eye color. It’s a simple thing you can do that will improve the way others see you.