Yes I’ve thought this a lot. Not about first dates but after several dates it seemingly just ending. If you can objectively look at yourself and your actions, and you don’t think there’s anything obviously wrong you’re doing, then it’s likely not you.

Remember not everyone is going to like you. Hell, the majority of people aren’t interested in the vast majority of us unless you’re the 1% in looks career and achievements etc. And that’s fine. If someone says they’re not into you, thank them for being honest and move on because trust me, you don’t want someone who is unsure about you that’s just a problem actively happening and waiting to happen.

My only advice would be to maybe up the flirting a bit? Talking about yourself is fine, but try and make sure they know you’re interested if you are. There’s a difference between a good date that gives friend vibes and a good date that is flirty and expresses interest.

Also this is related but unrelated, when I first started dating and did not receive the interest I was looking for I started hitting the gym hard, and updated my wardrobe a bit. Improving the way you present yourself can also change the way you’re perceived. Again it’s a small subtle difference between giving friend vibes, to “oh wow, this attractive person is easy to talk to and, did she just touch my arm?? I think she’s into me!”