Why is Seinfeld still so funny, when Dharma and Greg seems like a blast from the past? Why can I watch Tommy Boy 30 times in a row without getting bored, but Black Sheep was funny once, back in the 90's?
The answer is in timelessness. It doesn't necessarily mean one thing is good and another thing is bad, it just means one thing lives on, and often grows stronger with time, while the other might be good once, but simply gets tiresome or loses its cool.
If you're out to make something timeless, there probably is no set rules you can follow, and luck probably plays as much of a part as any, but here are my thoughts for getting started.
1. Tap into the Human Condition. Feelings, irony, and life milestones aren't necessarily products of the language of the day. They are unifying characteristics that run through any community, country, gender, race, whatever. Talk about things that helps us to identify commonality.
2. Be Relatable. Allow people to derive meaning in their own lives from the stories you tell.
3. Don't Go Out of Your Way to be Cool. Just be yourself. The cool thing continually changes, usually faster than you'd like. It's really more about attitude than the clothes you wear, anyway.
4. Be Consistent. And consistently great. If you allow one portion of your image to not live up to the expectations created in others, you're dead already. And you can't be timeless and dead. Not literally, anyway.
5. Take Risks. Nothing bland, and nothing that looked, sounded like, or felt just like everything else will be memorable. And you can't be timeless if you're not memorable. But,...
6. Be Familiar. Do things that feel familiar, things that make someone feel comfortable and draw them in. Then surprise them by doing something they didn't expect. Be remarkable.
7. Be Conversational. And I mean this in two ways, be conversational in your tone of voice, your gestures, your appearance, and be conversational by telling stories that allow other people to be conversational, too. Tell stories that are easy to tell.
8. Be Something to Somebody. This is about as cliched as it comes, but true. If we try to be too many things, we'll just become dull. If we can be something special to just one person, it's that much easier for that person to spread our story to other people who are of like mind.
9. Ignore the Rules. Rules change with time. Disregard them because following them will date you.
10. Don't Be a Slave to Technology. Use it, but don't abuse it. Technology can distract, and be a barrier to entry. Only use technology that adds tangible value to those with whom you're talking.