This is a good question, however there is not an easy answer. First off there are no set rules on how Cichlids are to be judged or who is qualified to judge. It has been talked about, but there are no written guidelines or approved judges. Rules will vary from club to club and from area to area. We are really naive about it out here on the west coast, where fish shows are few and far between. The few that I have seen were extremely small compared to shows that are happening in the East.
The fish is to be compared to what a perfect specimen of that species should look like. There are usually around 5 or 6 categories, each worth so many points, usually totaling 100. An example score sheet may look like this:
General Health and Condition 20 Points
Size 20 Points
Color 20 Points
Finnage 20 Points
Deportment 20 Points
Most of the categories are self explanatory. Deportment is how well the fish shows. Whether your fish comes out to the judge so he can see it, more points if they hold the fins up and display them. Less points if the fish is hiding behind the sponge filter and fold their fins in. Other deductions might be, scales missing, paired fins not matching, fins frayed or bent. Young fish loose points in the size category, older fish can loose points under General Health and Condition, and finnage. Young adults are your best bet.
Most serious hobbyists that show their fish, house the specimens by themselves to insure that they will not be missing scales, or have frayed fins on show day. Pick your best specimens, isolate them, pour on the wheaties, and hope for the best.