How?

[fdsfdfgsdfgsd]

I was wondering how do I create my own Second Life World, I want to create my own nightclub if that is possible i'm just wondering.

[Nalytha]

You can buy or rent some land and build your club on it. You will have to pay monthly cash if you buy land on the mainland. You will not pay monthly cash if you rent from someone. 

[Rolig Loon]

It's hard to answer a question like that without knowing what you mean.  Second Life is all one huge world, which you can see if you look at http://maps.secondlife.com/ and just keep zooming out.  You may buy or rent land anywhere in SL to create surroundings to your own liking (Well, almost anywhere.  Only Premium members can own land on the Mainland continent, but you may rent anywhere.)  If you want to open a club on your land, you are welcome to do that.  The major restrictions you may find are on private estates, where landowners typically have covenant restrictions (like local zoning codes in RL)  that define how you may use the land you rent.  If that's what you meant, I suggest that you spend time -- a few months -- visiting clubs all over SL to see how they work before diving in to open your own.  (Heads Up: Clubs are very popular, but they rarely make enough money to support themselves.  Club owners typically run them because they enjoy the club life, but they run at a loss.)

If that's not what you meant, and you really are interested in creating a whole new world, you won't be able to do that in SL.  You'll have to support a separate grid on your own private server, independent of SL itself.  That's a very ambitious undertaking, so I wouldn't recommend it unless you are technically inclined and already have a fair knowledge of how SL works.  Since your own grid would be completely separate from the SL main grid, too, there would be no direct way for clubgoers to get there from SL.  They would need to log in to your grid separately.

Unless you really did men that second possibility, I suggest taking time to read about land in SL and then maybe take Lindal Kidd's free class at Caledon Oxbridge University in world next Friday evening at 5 SLT.