Ok, I've never run nwod, I personallu don't like it. But I have run oWoD. So I'll give you some of the tips that I used.

First off, the best thing to prepare first is the location of the game. This is can easily be handled with a location all players are familiar with such as your city. This also leaves you to not have to worry about locations and distances to places, since most people will be using recognizable locations in your city.

After you have your city, if your players have already come up with their characters and a background on the character get those before hand. Then look at those and think what interesting stories that can be brought up from this. Someone's shady past coming back to haunt them and threaten their city is a good place to start.

After that, it all should start to fall into place. There are two theroies that I used to employ on this. Either one, think ahead of the players and try to force it in one direction. Or two, react to your players let them guide the way the story plays out. Needless to say the second option is the best one there. Basically act as a guide or a referee.

Here are some things not to do:

Don't stress. You're only going to hurt your game that way, and make it uncomfortable for your players.

Have fun. That is really what it is all about. You donned the mantel of a god, enjoy it.

Pick a small city nobody knows, do research, don't use too much of it.

I recommend Mage. So awesome to play once you and the players get shit together.

http://www.megaupload.com/?d=6bruaucr

Robin's Laws of Good Game Mastering

Here's your crash course in running games. Good Luck!

robins laws is an extremely good book. i enthusiastically second the recommendation.