Just add water.

Worldbuilding. It's one of the most enjoyable and frustrating parts of writing a fantasy story. It's essential for any story not set in "the real world", and you really need to do a bit of it for those stories to, because your "real world" is going to be different from my "real world", and they're both going to be diffrent from MTV's "the real world", which, when you think about it, actually has little to do with the real world. But I digress.

Fantasy worlds. Making them believable is not too hard. It's mainly a matter of internal consistency - does gravity work? Do dragons exist? You keep asking yourself questions like this until you come up with a framework of how things are, and then you stick to it. If wizards cast spells by waving their arms around, then when you bind a wizard's arms, then he can't all of a sudden cast spells by dancing a jig. If he IS going to break the internal consistency of your world then it needs to be a major part of the story - if you just gloss over it, it looks like you have no idea what the hell you are doing.

So, making it believable - potentially time consuming but not THAT difficult. Making them intriguing however, making them someplace that a reader will be interested in for 500+ pages... well, thats a bit trickier.

A lot of people say you should avoid making just another Middle Earth clone. It's good advice, but it's not always possible. I mean, if you want to write a story where humans are fighting some other, evil race, whether you call them snorgs, gnarlacs, or floozers, there are going to be inevitable comparisons to orcs. If you have wizards going around doing wizardly things, you're going to invite comparisons to Gandalf.

Even if you do somehow manage to avoid all of the Middle Earth tropes, you might find yourself being compared to LeGuin, or Moorcock, or other people that consciously moved away from Tolkein's model. And if you move away from them, you might wind up getting compared to more modern authors, like Martin or Jordan. Hell, you might even find yourself ripping off J.K. Rowling. And then you'll get sued!

Seriously, though. The more you try to make it different, the more you're going to look like your doing it just for the sake of being different. So just don't worry about it. If your story needs elves, then your story needs elves. No, you didn't invent the concept of elves. Yes, your elves are like Tolkein's, and the elves that populate your typical saturday night D&D game. But your story needs them, so in they go.

What you can do, what you must do, is give them a character that is all their own - you do this by doing a little thinking about their culture, their history. Its perfectly fine to have long lived, pointy eared treehuggers in your world, but you need to do some work. You start by asking a lot of "why" and "how" questions. Why do they care so much for nature? How do they live so long? Why do they shun civilization?

As you answer these questions, a culture will begin to take shape. As it takes shape, you'll naturally start filling in their history. You'll give them heroes, and enemies, gods and monsters. They will naturally start to diverge from the Tolkein archetype. Your readers will get interested in the differences, the unique ways in which your cultures diverge from what they are expecting to find. You'll cross the line from "ripped off from" into "inspired by".

I guess that's the crux of what I'm saying. If you look at the greats of fantasy, you can see the care, and the work that went into crafting their worlds. They weren't working in a vacuum either, though. Before Tolkein, there was Dunsany. Before him, there was Malory, and before them all are the collected myths and legends of the diverse cultures of the world. Everything is built on archetypes. We all stand on the shoulders of giants. However, if you put the work in, and fill your world with its own history, myths, legends, and cultures, it will be strong enough to stand on its own. It will draw the reader in, and give them things to discover.

Don't be afraid of working with fantasy archetypes - just be sure to put YOUR vision of the archetype forward, and do the work required to make that vision complete. Thats my take, anyway.

I just finished redrafting the history of AoR's world - from creation all the way up to the present day. And there are elves, and there are dragons. But I don't care, because they're MY elves and dragons.