A gaydar. The thing I don't have. Your gaydar is your ability to assess someone's sexuality. I personally struggle with this a lot, because I don't know ANYTHING about gaydar.
1) 💖💖💖
These hearts are a sign of someone being a member of the LGBTQIAP+ community.
2) Shoelaces
If someone says "I like your shoelaces," you say "Thanks, I stole them from the president."
This means that you're gay.
3) Sitting
If they can't sit on a chair, they're not straight (not always but a lot of the time).
Take me, for example. I'm on the chair, with my back half on the back of the chair, and half on the seat. My feet are sticking up in the air and are resting on the shelf above my desk, and my elbows are resting on the seat of the chair.
4) Dress sense
Gay men are stereotypically dressed well, but also they just act gay.
5) Refer to the comments because I cannot think of anything else.