You need a tripod and a camera capable to operate in manual mode and save RAW files. Compose and focus the scene, then change the focus to manual to ensure that the camera will not refocus the scene in the next shots. If your camera or your lens has a shake reduction feature disable it, it is not necessary.
Try to use a low ISO and a narrow focus, this shouldn't be a problem with the camera mounted on a tripod. In this case the images were taken with ISO 100 @ f11.
Take the first shot with the default camera values. Then move the camera dial to make another shot with a +2EV time. Do not change either the aperture or the ISO, only the exposure time, do it gently, don't move the camera. Repeat again but this time with a +4EV time.
Download the files to your HD and open the RAW with 0EV exposure, set the depth to 16 bits/Channel and in the color space you can pick AdobeRGB or sRGB. In this case have I used AdobeRGB. Develop the image with the default values just by clicking on Open image.
Now go to Menu File > Place... and select the +2EV photo, move the exposure compensation bar to the -2 value to match the exposure with first file opened.
Click the green icon to accept without changing anything and rasterize the layer, right-click on the layer and select Raterize layer. Create a layer mask for this layer to use in the next step.
Go to Menu > File > Place... again and pick the +2EV file again. This time use the default exposure value. With the photo placed into the document select all (ctrl+a) and copy (ctrl+c). This layer is not needed anymore so remove it. Select the layer mask previously created holding the Alt key and paste the image (ctrl+v), you will see the +2EV image in greyscale.
With the mask layer still selected press ctrl+i to invert the image and use levels (ctrl+l) to reduce the white levels, in this way the not noisy zones are totally unmasked.
The image has improved a lot but there is still some noise in the dark areas.
Repeat the same process this time with the +4EV photo. Place on the document, setting the exposure compensation to -4.
Open it again, this time with the default value and use the opened image as mask, invert and use levels again to improve the mask.
The resulting image has an awesome tonal range with a very low level of noise, but now it looks too dark.
On the layers tab click the little icon to create an adjustment layer, select curves, and modify the curve to make an exposure compensation.
Make another adjustment layer with curves again, this time make a "S" type curve to improve the contrast.
Finally make another adjustment layer this time picking Photo filter and selecting a cooling filter to reduce the yellowish tone.
If you zoom in a lot you will see that there are still some ugly artefacts, not too much noise but still disturbing if you go for a large good quality print.
To get rid of it merge the layers and go to Menu > Image > Mode > Lab color. Go to the channels tab and select only the Lightness channel, select Menu > Filter > Noise > Reduce noise... and apply the strength necessary to remove those artefacts.
Set the image to RGB mode again and save.
Here is the final image
And here is shown how much the image was improved