In that case, each person chooses their pronouns for their own reasons, and even if we brought in another person who only uses it/its pronouns, they’d mean something different to it than they do to me, though there may be similarities.
If you want to figure out what pronouns you like best, I’d recommend imagining yourself in the third person, and describe yourself using different pronouns, and figure out which ones you like best, if any. Or have a friend or someone else you trust “test” pronouns with you – talking about you in the third person with different pronoun sets.
Or you can write a paragraph or so about yourself like someone else is writing it, then switch out the pronouns with other ones.
Sometimes you’ll know right away if the pronouns are right for you, sometimes it’ll take a while to find ones you like. And some people just have no preference at all, and will just go with “the path of least resistance” (aka, go along with what people call you), or will even accept all pronouns equally.
There’s no set “meaning” for it/its pronouns, or ze/hir, or xey/xem, or any other pronouns. You are the one who defines what they mean for you. Even if it’s something as simple as “I like how they sound” or “I think they look cool”, that’s good enough if they’re the ones (or multiple, there’s nothing stopping you from using more than one set) you choose!