I have good gaydar, and it's not always easy to pick out some people based on looks. I know women who look straight and are lesbian. I can usually tell if they send out signals or respond to mine -- it just kind of comes naturally, and I really can't explain it. I can usually tell if a woman is lesbian or not via signals. Saying that, sometimes you run into bi women, and I've met gay women who aren't very good with signals (noticing them, reacting to them, or giving them out). Just like straight people have signals, too, and some straight people don't respond at all.
I think it's just different cues one picks up. It's body language, mostly, and the way you look, speak, and so on can also have a role in that. We pick up or give out a lot of cues subconsciously. I find I don't purposely give them out.
