To give you a head start.. this photo was taken at pitch black. couldn't see the mountain at the beginning of the exposure. the rising sun helped bring the mountain in.
Exposure: 30 min
One thing I've had to watch for when focusing is not using auto-focus. and not just setting it to max infinity. depending on the lens, it will let you go over infinite focus (both my 10.5mm and 17-70mm do)
If you have LiveView use it to focus the lens. and use a remote of timer to trigger the camera. just the slightest movement in the camera will blur the picture.