As a lucid dreamer for seven years, here are the ways I check if I’m dreaming:

Turning on a light: Lights don’t work the same in dreams. When I try to turn one on, it doesn’t shine like it should. But this method never worked well for me. Sometimes the bulb would glow a little, and I’d just wonder if I was dreaming or if the bulb was broken.

Reading text: In dreams, it’s usually hard to read words or numbers. Looking at a digital clock is a common test. It worked for me at first, but now I can read and write clearly in my dreams, so it doesn’t help anymore.

Asking the date: This is still my best method. I ask people what the date is, and no one ever knows. Even after I realize I’m dreaming, I still have a hard time remembering the real date from waking life.

Looking in a mirror: Mirrors act strange in dreams. I often can’t see my reflection, or it looks weird. It’s creepy, but it helps me realize I’m dreaming.