What are the conventions of the Superhero genre?

The word "Superhero" dates back to 1916 but it wasn't until 2009 where both Marvel and DC comics jointly registered "SUPER HEROES" as a trademark. 

A superhero is a person who is dedicated in order to protect the public from harm. They usually have a secret identity so the public cannot guess who they are, but whilst saving people from harm, they usually wear a costume and mask and have a signature trademark (such as a bat for Batman).

The Superhero genre itself does have several conventions including:

• Having either extraordinary powers, equipment or skills - a wide selection of superpowers including flying, super strength, x-ray vision or even the unnatural animal powers (such as Spiderman's uncanny ability to climb walls and shoot webs out of the palms of his hands). However a person does not need superpowers to become a superhero. Instead they could have special items (such as Wolverine's claw or Capetian America's sheild). Or a superhero might not even have a special item, but may just be incredibly skilled (like the Black Widow for instance).
• A Moral Code - when a superhero has a willingness to risk their safety for another person/group of people without having a reward. The code often means they won't kill or use lethal weapons against another person.
• A Secret Identity - a superhero will almost always have a secret identity (like Superman's alias is Clark Kent) to help protect their close friends and family. The superhero will often have a confidant who they will have sworn them to secrecy.
• Supporting Characters - a superhero may have a sidekick (for instance Batman and Robin) but this may become a complicated relationship due to the superhero's dual lifestyle.
• Motif - A motif will be individual to a superhero and this will distinguish them from a different superhero. It can become their signature trademark and will often affect their lifestyle in some shape or form. 
• Financial Support - often independent wealth (Batman or Iron Man) or having an occupation that requires minimal supervision (Clark Kent who is a reporter)
• Headquarters - this is a place where a superhero (or sometimes the supervillian) can have their base of operations. Their headquarters are often disguised so they can avoid detection from the general public or even their enemies! The superheros will often deck out their headquarters with top of range/alien technology however for some superheros, they will not have a permanent headquarters but rather a mobile base of operations where they can store their costume, information etc.
• Backstory - a backstory will often add depth to a superhero's personality and usually explains how the superhero got their powers (usually in a tragic/freak accident) or how they got spurred onto wanted to become a superhero.
• Achilles Heel - this is also known as the superhero's specific weakness which is an important plot device which the supervillians use to unhinge the superhero.
•  Rogues Gallery - the superhero has to normally fight a set of villians (known as rogues) on a regular basis. Often a superhero has an arch enemy who is more troublesome than the other criminals and will often be the doppelganger to the superhero's personality (e.g Batman is silent and dark whereas the Joker is flamboyant and garrulous).
• Costume features - a superhero's costume automatically makes them more recognisable to the reader, and often the costumes are a specific colour set to make them more iconic. They also normally wear the following items:

1. Masks to protect their secret identity.
2. A symbol to make a superhero more distinguishable. 
3. Form fitting clothing (often referred as spandex).
4. Even pants over their tights.
5. Interestingly enough, although capes are often associated with superheros, very few actually wear. As both Batman and Superman wear them, they were the most popular of the superheros and as a result, the cape quickly become associated with superheroes.

• Role Playing Games (RPG's) - in RPG's, players often organised superheros into categories based  upon their skills and assets.