As a Camera Club Judge I look for the following in a Photographic Image.

My first aim as a Camera Club Judge is to encourage Amateur Photographers like myself to achieve the best image possible and get enjoyment out of our Hobby and Craft.

When Judging I look for the following;
Does the image have impact on its own and or against the others Images being presented on the night.
Is the image technically correct both in Composition and Post Processing remember there are limited things that can be done Post the Camera.
When it comes to Sea and Land scapes the HORIZON line must be correct. Many an excellent Image is let down due to the Horizon line not being correct.
Likewise Buildings both interior and exterior must not lean unless you have deliberately put the image on a diagonal to give an artistic effect. Slight off Vertical is like a poor Horizon line and downgrades the Image.
Portrait (People) Be careful what you include in your Image.
Jewellery can be some times over powering.
Too much of the upper body can also over power the image or at least detract from your Models   face.
Hands are better left out of the image as they can look over size to the rest of the portrait.
Back ground should be dark and featureless or at least totally out of focus and have no highlights.
Watch out for Flash Shadows on the back ground, be sure the subject is well forward of the back ground surface.
Watch for harsh shadows across the face, nose and eye areas.
Look for emotion in the subjects Face / Eyes and get your Model to interact with you and the Camera.
Face and Eyes must be Sharp and a catch light in the eye give life to your model.
 

Focus
Both in general and in particular Close Up/Macro, the main part of the Image/Item must be Sharp.
Animals and Birds, the Head/Eyes must be Sharp and a Catch Light in the eye give life to the subject.
Flowers etc. the majority of the flower must be sharp in particular the centre.
Land and Sea scapes, the foreground must be sharp so think about the Aperture setting to give you a good depth of field and also use a Tripod whenever possible. 

Presentation
Prints - Borders or Mats must be of a Colour/Size which will enhance the Image.
When using Mats make sure they are cut cleanly.
Finally when a Mat becomes damaged discard it, as these also can downgrade your Image.

I like to see Photographers break away from the standard stereo Image and push the boundary without losing any of the above.

Finally, Judges can see images differently and remember it is your Image and in the end you are the one that has to be satisfied.