So this is under the impression that it isn't via apps/online dating, and done in person.
If you can't tell if someone is interested/LGBT, how do you determine it so?
Do you come off as/do people suspect you are gay/lesbian/bi/etc. yourself?
If you're in a non-gay venue (bar/club (would you even be found there?), how do you determine how you will act/make your move? Are you more subtle about it (if bi, or in general)? Or don't care, if you hit on someone?