Apart from presenting a problem in that your characters sound the same or worse if you're in the game master's seat - everyone is sounding the same. Rural peasant, evil knight, thousand-year old dragon, goblin pirate, elven princess - all a cornfed games master.
It's time to shake things up. It's called role-playing for a reason. Even as capable as we are, not everyone is born Robert Downey Jr. So how do you portray someone you're not?
Go to character traits. How would they act? Women like to appear attractive. Who doesn't? These simple truths need not be the be-all and end-all of a character. Women tend to think in terms of relationships and organisation while men tend to think in tasks and comparisons.
Note the use of tend, examples of scatterbrained women and lazy men exist - distinctive because they are at odds with the normal. Caricature and stereotype are attempts to hide the fact you haven't done your homework. If this is someone you're playing, that's just lazy and automatically cheesy. If it's someone you're writing, expect them to come over a bit flat or worse, cheesy.
Respect your sources but don't rip them off. If you're drawing on Angelina Jolie's version of Lara Croft as a half-elven swashbuckling rogue - have her swagger around men, speak in aristocratic tones and give her an impish smile when she's about to give someone their comeuppance.
She doesn't need the shorts to get the idea across.
Show, don't tell is your key. If you fear you're basing a character on just one source, mix it up a bit with another character (keep this to two distinctive people). Add a bit of Keira Knightly's Elizabeth Swann; dignified, devoted to her man and fiesty and go from there.
Assuming you remember what the opposite sex is and can get past the stereotypes of violent hatred for the opposite gender, complete promiscuity or frigidity, really irrational behaviour and mind-blowing greed and selfishness then you can have some fun. If you're playing the opposite sex, think of someone you admire or that you want to understand a little better - why would you want to play someone you'd hate? Games masters are exempt from this one, obviously.
Admirable women - Harriet Tubman, Joan of Arc, Florence Nightingale, Xena Warrior Princess.
Admirable men - Bruce Lee, Mahatma Gandhi, Julius Caesar, Cucullain
Over at Dungeon's Master, the dilemma of playing someone of superior intellect when in fact you're of average intelligence means you start noticing things or planning ahead to anticipate your strengths and weaknesses. If there's a group, have them use tactics. An example of this in 4th edition D&D is the warforged have Intimidate skill - in combat, using this skill takes a -10 penalty against hostile foes (making the attempt a bit limited by yourself). Now if you have maybe four friends banging on their shields (and making Aid Another checks) - you have a bit more oomph behind the Intimidation check. And it's a cool scene-setter as well.
Equally if you're playing someone of different smarts to yourself is another dilemma - the criticism that some people play their brick walls as smart as their rogues - or worse, their wizards - is one heard in certain areas. Dare to be stupid or focussed on the wrong things at times (just not life-or-death situations eh?) and watch your character become memorable.
Because you're a red-blooded woman doesn't mean you don't want to play a gentleman who prefers male company (prevalent in slashfic authors I'm told) or vice versa; you don't have to be of a different gender to appreciate what's on offer. Or you might want to play a character who to paraphrase the movie Spartacus likes "...both snails and oysters." Avoid cheesy stereotyping and do some research into those attitudes; what you find may surprise you, like the Greek charioteers called the Sacred Band of Thebes who were once believed invincible.
Many people have wondered why there has been much dancing about in terms of gaming and race. Tabletop RPGs have arrived a little late to the game, partly due to political correctness, partly due to the Hollywood roots of gaming's inspiration.
Ironically, Robert E. Howard is ambivalent - while the women are rarely fierce combatants (Valeria, Belit and Red Sonja are unusual) but the pirates and mercenaries that Conan works with or fights are a mixed bunch. White Wolf brought this into the light of day in Vampire: The Masquerade (and later in Mage: The Ascension) but the fun needn't stop there; other games (D&D) have realised there's a whole world to bounce off.
Different cultures can be good. They may also not need your brand of civilisation. There is a time and a place for cannibal tribesmen but it need not be every island. Equally, organising your gangs along ethnic lines may be fitting to your urban setting but consider the effectiveness of crossing the tracks as well. Why not have the gangbangers do some leg-breaking for the depleted yet wealthy Yakuza gang in return for cash?
Time to wrap it up.
- There is a time and a place and in some cases it may not even be relevant to the story. Case in point - Albus Dumbledore was outed by J.K. Rowling at the end of the Harry Potter series even though he died in the previous book with no real indication of this previously. Close friendships between men need not necessarily imply homosexuality...
- Nobody wants to be that guy or girl into hot elf-on-ogre action or who uses the templates and hybrid races as an excuse for experimentation. Instead write it down, password it and and if you're really good, see if you can get a publisher. Under a pseudonym naturally!
- As always, respect the boundaries of your audience and fellow players. Not everyone is as willing to experiment as you may be or wants the details thrust in their face as it were.