More internet links...

http://mediagoldfish.blogspot.com/

Another blog that has looked at the conventions of superheroes.
Characters often have a back-story which explains their upbringing or how they got their powers in a short format. This provides us with a good idea of what sort of character they are, it also links the hero with the arch-nemesis, who are usually friends in the beginning.
Their appearance is very important to how we view the character. Heroes usually have big muscular physiques, chiseled features, bigger eyes, they are essentially the perfect human.
Names also guide our conception of a character. Heroes often have alliterative names, such as Peter Parker and Clark Kent. (In heroes - Peter Petrelli)
The arch-nemesis, however, is often not muscular and attractive, their eyes are smaller, they have wicked grins, they are often not human like creatures, features are distorted (particularly the head) and they are often dressed and speak in a much more sophisticated fashion than the hero.
Of course the defining feature of a superhero/villain is the costume. Not only the physical costume, but the alter-ego. A superheroes costume usually consists of a tight fitting number, that has some resemblance to their super-name.

The storyline of most superhero narratives are as follows. Establishing story, relates the characters to each other and explains how they got their superpowers. The love interest is usually introduced here too. The Hero goes out and saves someone, sparking a reaction from the nemesis. They attempt to kill the hero, someone he knows, or the entire world. The superhero tracks him down and tries to put a stop to the evil. The plan backfires and the hero is caught, on the brink of death or simply losing the fight. The villain reveals his plan to the hero in a laborious monologue. The hero over comes his problem, defeating the villain and stopping the evil plan. The villain may either escape, or be arrested, they rarely die. The story finishes with a scene with the superhero, with the love interest/collegue, talking and having a happy time.