I don't know how to Light Graffiti Nikon D3000?

So, I was able to do light graffiti before. I'm not really skilled with my camera yet But I took some cool shots of light graffiti…

http://www.facebook.com/...1309345428

And now I don't know what to do. I've set it up on Manual mode, but whenever I do light Graffiti it doesn't do the same quality that I did before (Look at link) & I don't really know how to chance the shutter speed & aperture. I mean I've done it but i don't know if its on whenever I'm taking light graffiti.

I hope this makes sense.
Hope someone can help me!

Added (1). Thank you for both of your answers.
I seriously do want to pick both of your answers as "Best Answers" But I don't know who to pick!

The way light graffiti is produced is to set your cameras shutter speed to bulb and hold the shutter open as long as you need to create the graffiti you wish.

If you are NOT using an assistant, you will need a remote shutter release so you can be in the frame of the camera and hold the shutter open at the same time

Adjusting the lens aperture will be the way you control the saturation of the light as you wave it around

If you have been able to make light graffiti before, those same skills still apply

This is part of one of my best answers before on a similar situation. It doesn't matter what camera you are using, the same principle applies:

Best Answer - Chosen by Voters

So, in order to do it:

1- Set your camera on a tripod or stable position.
2- Set it to Manual mode
3- Set your ISO to 80 / 100 (might have to mod this later)
4- Set your aperture (choose a 5.6 as a start) (will mod later)
5- Set your speed on a long exposure (several seconds) (will mod later)
6- Forget about what the exposure meter of your camera says
7- Set camera on Self timer
8- grab lights of different colors
9- Shoot and move the lights around

Check photo, and adjust accordingly!

Enjoy!

To fine tune your image, do a first test with ISO 100, aperture 5.6 and several seconds exposure. Take a test shot and depending on whether it is coming out too dark or to lighten, then adjust your shutter speed or the aperture if decided.

Let us know how it went!