The first thing you need to do is pick what you're going to write your Introduction about. Don't be worried if you think no one will find it interesting. In fact, if it could possibly be compelling to anyone, your best bet is to forget the whole thing and come up with something else. Another good tactic is to pick something that everyone already knows. Once you've chosen your subject matter, perhaps something like "Care and Feeding of Accordions", it's time to get writing.
The first thing on your list is to head off to Google. You're going to need lots of links to make your article look more authoritative. Sure, anybody could find those links themselves with a minimum of effort, but it will make it look like you put some work into this article.
Now, to write the actual article. You can't just charge in to this, though. You need to write a good introduction. This article will show you how, from writing a good "peg" that the story centers around to trying desperately to show people why they should care what Geocaching is.
You can start with the obvious: a quick story about how you got into the subject yourself. A quick little story about how you and your older brother/barber/parole officer were chatting and he mentioned the topic, but with fervor and passion. Intrigued, you checked it out, only to learn that he wasn't alone, dozens of people around the world shared his passion for sewing machine collecting, and now you feel like one of them!
Or you could take the less personal route and write your introduction textbook style. While not as convincing as the personal story idea, it gives you the authoritative tone that many people who are interested in what your writing about like to hear. Of course, you have to have them interested first, or else you come off as a snobbish bore. Admittedly, this is easier said than done when discussing Alf pog collecting, but you're going to have to do it.
After you've established why you're enthusiastic or authoritative on collecting He-Man and the Masters of the Universe breakfast cereal boxes, it's best to next display a brief history of the subject. If, for example, your subject is "An Introduction to Bottled Water", you'd write a brief bit about the Fluoride scares, Cholora, Hepatitis, and Crystal Pepsi.
Of course you're going to want to break up the sections in you history. It's best, especially on sites like K5, to use all bold letters at the top of each new section. That way people will be able to follow the flow. You don't want them getting confused about your Butterchurn Restoration for Fun and Profit.
After a dazzling intro and informative history, you should tell the reader how he (or, indeed, she!) can get involved. This is where you link to the PETA, Abercrombe-and-Fitch, or NAMBLA websites, hoping that many others will join your cause/sport/hobby/cell block.
However you end up writing your Introduction, you will have to make sure that the article has relatively decent grammar and spelling. Many an otherwise decent article has been voted down because the author showed a basic lack of understanding of the English language. Some think this is not fair, but you do have to pander to the kurobots here.
Once you're done writing your article and spell checked it, is it time to submit it yet? NO, absolutely not! You also need to add a bibliography at the end with your sources about your fine Introduction to the end of your story. No one will read any of these sources, but they sure do look impressive.
NOW you're finally ready to submit. For maximum effectiveness, use the edit queue. Even if you have no intention of editing your perfect story in any way, it is proper form to leave it in the edit queue for the full two hours. Some people might complain, but they're just joshing you. I wouldn't worry about it. Your Introduction to Tapeworm Farming is finally done, and by gum, it's the best damn Introduction since the one that got posted yesterday!
Now go get 'em, tiger!
Bibliography:
Bouillabaisse
Self-whoring link
This link has barely anything to do with anything
Some other activity
Fat Chicks in Party Hats
Neuticles
The Bill Gates Fanclub
blah blah copyright Captain_Tenille blah blah free use blah blah