So you've written your jokes. You've practiced in the mirror. You're ready.
Welcome to the Open Mic. Here is what's going to happen.
The Environment
Open mics are grim. They are usually in the back of a bar, a basement, or a coffee shop. The audience is mostly other comedians waiting for their turn. They are not there to laugh; they are there to work. Do not be discouraged by the silence.
The "light"
Somewhere on stage (or held by the host), there is a light. * The Light: This means "You have 1 minute left." * Flashing Light: This means "Get off the stage NOW." Respect the light. If you run over your time, you are stealing time from the next comic. Everyone will hate you.
The Set
Do not try to improvise. Stick to what you wrote. Hold the microphone close to your mouth (literally touching your chin). If they can't hear you, they can't laugh.
The Aftermath
When you get off stage, you will have an adrenaline crash. You might feel elated or depressed. Shake the host's hand. Buy a drink (support the venue). Watch the other comics. Being part of the community is half the job.
Good luck. You're one of us now.