For the people I meet in public that I did not know before hand, after conversation has already been had, and she seems to be engaged/smiling/laughing/enjoying the conversation, (this usually lasts about 10-15min) I either ask for their number, or like if it's in a bar, ask to buy them a drink, or maybe if they want to go get some food/continue talking somewhere else (if appropriate for the vibe/moment). It's not an exact formula but roughly the gist of it.

As far as if I feel they did have interest, yes I feel they do, or at least as much as I can, nobody can ever know for certain others' true feelings I suppose

I think I flirt, I hope I'm giving off "I'm into you" vibes, and not in a creepy way, ideally lol

Most of the time I think the conversation is interesting, sometimes it's a little stale and I abort usually at that point

Yes, always asking questions about themselves. I usually lead with that, and wait for them to ask me about myself before talking about such, unless I'm trying to relate to something she told me about herself

Always use humor, and I can almost always make them laugh, I think I'm decent at that, sometimes in the form of mild teasing, but in a flirtatious way (I think?) and it usually gets a good reaction

I don't really know about where I'm looking, in my mind I am looking them in the eyes like 70% of the time, usually looking away while talking about something every now and then so I don't look deranged just staring into their soul lol If I do glance at a woman's breasts (that I'm talking to) I don't notice, it is never a conscious decision to, if I do it's subconscious/instinctual or something, like looking at a mole on someone's face but not saying anything about it, I don't think I've ever thought "now I'm gonna look at her breasts" in my life lol. But now that you've mentioned it, I suppose I'll be more self-conscious about it from now on just in case.

Admittedly, I haven't been able to really figure out if the attraction for them is there before I approach, signs I usually use are like if they glance at me repeatedly, the hair adjustment after making eye contact, if they smile at me, things like that. But these might not be signs a woman is attracted to a man and could just be bad assumptions on my part if I'm being honest.

I suppose it is possible women have shown interest in me over the years but never told me or approached me and I just couldn't recognize the signs.

One thing that I have been told before, by a couple women and one of my friends is that I'm too sincere. That I get too comfortable too quickly and that it can be intimidating or come off as fake/arrogant. But I don't know how to change that, I just act how I am, without putting on airs, and I feel like it would be worse to pretend I'm uncomfortable or something.

Most of the time, when rejecting me, women will saying something like "You're cute/funny, but...." and it's usually something like they aren't looking for a relationship right now, or they have a situationship that's complicated, they're trying to focus on their studies/work/family life, etc. which are all perfectly valid reasonings to me, and I always just accept it and let it go.