There are limited forms of Dragon etiquette that are commonly used.
There is the comic look at dragons which involves killing and eating humans. While this is funny it presumes that dragons are ignorant of human society and the many successful dragonslayers romping around throughout fiction.
There is the "dragons are the most dangerous creatures ever" look at dragons. Dragons don't really have etiquette. You just die or can not approach them. This often combines with the "dragons a big dumb lizards that breath fire" look at dragons.
Finally there is a in-depth look at dragons that a few people have taken. Of all the sources I have seen Dungeons and Dragons (
www.Wizards.com) has taken the most in depth look at different kinds of dragons but you'll want to familiarize yourself with the d20 license before you touch that. Other really in-depth sources have been mentioned previously. However they treat dragons as the most complicated, intelligent and powerful of creatures.
I saw a fantastic documentary on dragons on one of the learning stations. The dragons are all computer generated, naturally, but it treated them as if they were real and went over their mating habits, social graces, incubation and other aspects of their lives. I don't remember the name of the program but it was very professional and I wouldn't think it would be too hard to hunt down on google.
One big decision you will need to make is how many kinds of dragons there are. Many just stick to one dragon, while others have dozens. The more dragons, generally the more complicated and intelligent they are. The need for diversity forces some to be highly intelligent while others become dumb as rocks.
Mark Charke