You can have the best punchline in the world, but if you mumble it into your shoe, nobody will laugh. Delivery is the vehicle that carries the joke to the audience.
1. Conviction
The number one rule is confidence. If you don't believe what you are saying is funny, neither will they. Even if you are faking it, commit to the bit 100%.
2. The Pause
We've talked about timing, but the most important pause is right before the punchline. It signals to the audience "Get ready, here it comes." * "My grandfather has the heart of a lion... (beat)... and a lifetime ban from the zoo."
3. Dynamics (Volume)
Don't be a monotone drone. * Whisper for intimacy. * Shout for outrage. * Speed up for manic energy. * Slow down for emphasis. Variety keeps the brain engaged.
4. Eye Contact
Look at the people you are talking to. It creates a connection. If you are on stage, pick three people (left, center, right) and rotate between them. It makes the whole room feel included.
5. Don't Laugh at Your Own Jokes
Unless you are breaking character, try to stay neutral. If you laugh before the punchline, you ruin the surprise. Let them laugh. You are the drug dealer, not the user.