For steady shots, you need tripod or at least something steady enough to put ur cam on.
For right exposure, ermmm, guess ur cam's meter must be right, this is done by FE for around 60 sec exposure?
For sharp image, I used 28mm lens push the aperture all the way down to 18 or 22 cant remember, but as u can see from all light stars, you know its damn small.
There are many ways to achieve this effect, feel free to try.