Superhero comics have a ton of useful tropes that could easily be adapted to other genres.
Want your players to know when an NPC is important? Give that NPC an alliterative name. Bonus: It will be easier for everyone (including you) to remember it.
As far as PC names go, Superhero code-names are usually nicknames or titles of a sort. I’m often surprised at how rarely PCs have nicknames or titles. One of my favorite PCs was a highish-level rogue/cleric of Tritherion in a Greyhawk campaign. I decided that his priestly title was Harbinger (which suited the god and the PC’s role) and the DM generally had people who recognized him or his symbol of office calling him that – it added to the tone a great deal.
There’s also nothing wrong with non-superheroes with secret identities. Look at the Scarlet Pimpernel, the Lone Ranger, or Zorro. Moreover, villains with secret identities are commonplace, so why not heroes?
Create a rogue’s gallery for your PCs. In comics, rogues galleries often share a theme that mirrors the PCs in some way. Batman’s rogues are often either reflections of Batman’s animal-emblem (Catwoman, the Penguin) or reflections of his psychological instability (the Joker, Scarecrow, Two-Face). Superman’s rogues may concentrate on the intellect (Lex Luthor, Braniac) or be reflections of him ‘unhindered’ by his moral compass (Bizarro, Doomsday). Spider-man often faces science experiments gone awry – like the one that created him (Green Goblin, Doctor Octopus, the Lizard). The Hulk typically faces other gamma-irradiated beings (Abomination, the Leader). How do you do this in an RPG? Well, there are a few ways. Perhaps most obvious is the ‘evil opposites‘ route. More subtly, look at an aspect of each PC and twist it – either flipping it to its opposite or magnifying a flaw in it. For example, a wizard who focuses on fire spells might be countered with someone that summons elementals or an enemy focused around a different element. A character motivated by revenge against marauding orcs who slew his family might face the last orc from a tribe slaughtered by adventurers, a human raised by orcs, or someone (not an orc) whose family the character killed.
Also, few things motivate players to beat a villain more than having the villain beat their PCs. This is a fairly common superhero trope, where the hero faces off against a villain, gets beaten, and then needs to do something (even if it is just regain confidence) in order to beat the villain on their second match-up.
Other villain-related tropes you can use: Villain team-ups (usually with internal discord/betrayal), anything from the Evil Overlord list.
When a superhero is rich, he is usually so rich that money is never an object (see Batman, Iron Man, Professor X, Reed Richards). When a superhero is poor, the need for money often motivates the plot (Spider-man is the classic example here). Most superheroes are in-between – and, for them, money is simply never an issue. They have enough to do what they need, as long as what they need is not too ostentatious. Unless you are playing a game that focuses on mercantilism (or kill things and take their stuff), you might want to consider those three categories for PC wealth. In many games, anything more finely tuned will be unnecessary.
Another superhero trope is that equipment is part of a hero’s identity. We don’t imagine Captain America without a shield, Green Lantern without a ring, Iron man without armor, or Batman without those wonderful toys. Now, the precise nature of the equipment might change. Captain America might lose his adamantium-vibranium shield… but he’ll replace it with another one (probably temporarily). Iron Man might modify/upgrade his armor. Green Lantern might… ummm… get nine more rings… Anyway. Yeah. In any case, few superheroes go out and actually, you know, buy things off the shelf (much less take things from their fallen foes) to use in superheroing. In contrast, PCs in fantasy RPGs are usually constantly upgrading their equipment. One eggect of this is that they change their look and capabilities every time they find a new magic item. This can lead to identity drift – the fighter who was the guy who wore mithril chain and carried a magical, flaming axe becomes the guy who wears magical plate armor and carries a dancing shield and magical greatsword. As an alternative to trading in items, consider letting your PCs upgrade magic items they find early in their careers for a discount… or even upgrade those items automatically in a low-treasure game.
Speaking of identity and character-branding, you probably don’t want to dress your non-super PCs in spandex or the like (unless you’re playing a pulp SF game… or something… naughty), but that shouldn’t stop your PCs from having distinctive images. You can come up with a ton of excuses for why your PC wears a particular symbol, say – perhaps it is a family crest (Superman), something designed to evoke a reaction from enemies (Batman), a symbol of an organization (Green Lantern, Captain America), a symbol of something that started him on her path as an adventurer (Spider-man, the Flash), or a symbol of team membership (Fantastic Four, X-Men). It could also have practical purposes, serving as a target in a highly-protected area (the Punisher, Batman, Captain America). Even without a symbol, a particularly distinctive article of clothing or color scheme (Dr. Strange, Elektra, Balck Canary, Green Arrow) does a good bit to make a character distinctive.
Other tropes to steal:
submitted as part of the RPG Blog Carnival.