It's taken me a few months to perfect this technique so don't expect to get it right first time. I've attempted to cover all of the bases by explaining things in bullet points, I hope you find it readable, easy to follow and a useful tutorial.
1) Set up your camera on a tripod (You can do handheld, but I find it tricky and too much to think about)
2) When mounting to the tripod, don't mount the camera body with a long lens overhang, this won't be steady enough when the shutter is released. Where possible, mount the lens to the tripod using a lens tripod ring.
3) It's better to have a long focal length lens. 200mm is perfectly OK, but generally speaking, the higher the better. (I used 200mm for this shot).
4) Remember the Moon is moving so you will be constantly repositioning and you need a fast shutter speed; around 1/125. You'll be amazed how quickly you see it moving through your viewfinder when using a 200mm lens.
5) Shoot in RAW mode to give you maximum quality and control - do not shoot in JPG the quality is not high enough.
Taking a light readings:
6) Set your metering mode to Spot, align the Moon to the centre of your frame and take a light reading
7) Whatever the reading, you need to under expose by around two stops or more - you need to experiment with this
8) Light readings for a full Moon are around 100 ISO, f/8, 1/250 sec - more light is required for crescents and half moon.
9) Focussing on the moon is the biggest problem by far. The camera's auto focus system is useless for this assignment, you need to adjust the focussing ring manually.
10) Focussing problems can also come from the vibrations transmitted buy the shutter release. Use a cable or wireless shutter release or if you don't have one, use the camera's self-timer to release the shutter. Don't press the shutter with your finger as this may vibrate the camera, especially if your camera body is mounted on the tripod with a long lens overhang. (You can buy a wireless shutter release for around £20).
11) When you're ready to begin shooting, set your camera to "Live View" mode and magnify the image on the camera screen to ten times to assist with focussing. (Now you'll really see the Moon moving across your screen)
12) "Live view" utilises mirror lock up and devours your battery life. Make sure you have a spare
13) Try to keep the Moon in the centre of your shot to prevent any lens distortion. If you have the Moon positioned at a far side of your shot, you may experience ashperic aberrations where the Moon may be egg-shaped rather than round and it will also be out of focus.
14) Take several shots using a remote shutter release and manually change the focus after each shot
15) Because the Moon is 250,000 miles away, it's going to appear small on your image therefore you will need to crop afterwards in Photoshop or other editing software, that's why it's essential to shoot in RAW so the quality is retained.
16) Take a torch, you may not be able to see your camera dials in the dark
17) It gets cold standing around pressing buttons, wear the appropriate clothing
18) Planning: Knowing when to shoot is essential, you have to be available when the Moon is visible
19) Practise is essential, don't expect to get it right first time
Special Note: Shooting a full Moon is by far the most difficult. This is because the sun is shining face on and therefore there's fewer shadows being cast to bring out the detail in the craters. The best time to shoot is between 1/2 and 3/4 full. Don't wait for the full moon, try a few just before.
I hope this tutorial helps you with taking some great shots of the moon, they can be extremely rewarding.
PS, please feel free to add your shots of the Moon together with your experiences and make any suggestions to make the tutorial better; I have skin like a Rhino and I don't take offence