• Use a tripod.
• The moon is deceptively bright.  Use a much faster shutter speed than you would expect.  I suggest trying 1/250sec at f5.6.
• Use a cable release or i/r remote if at all possible.
• Remember that you'll be able to crop a photo, making the moon larger in the process.
• If your lens is "Image Stabilized," take note.  Ironically, some older lenses will create extra camera shake when mounted to a tripod.  You should turn IS off when mounting on a tripod.
• Your SLR camera may have a mirror lock-up feature.  It helps reduce vibration in conditions like this.  The first shutter press flips the mirror.  The second takes the shot and returns the mirror to its default position.
• Note that even a good lens may be "soft" when zoomed to it's longest reach.  Not a lot you can do about this, except consider cropping from a shorter zoom.
• Keep an eye on your lens.  Some lenses, like the one I was using, tend not to hold their zoom when they're tilted beyond a horizontal position.  If your lens' condition is particularly severe, it will prevent you from getting a good shot.
• Crescent moons allow you to capture the mountainous contour at the edge of the moon's horizon, yielding some nice results.
• If you're good in Photoshop, consider layering an under-exposed shot with a properly exposed one.  I don't know, but it might be able to reveal some nice shadow detail.
• Look for opportunities for passing cloud cover to add extra interest.  I've seen some amazing opportunities in the last few days, but haven't been in a position to capture them.  You'd be surprised how quickly cloud conditions can change.

This photo is also available as wallpaper.