So today, I go to FanFiction.net, looking maybe for some CellXFrieza yaoi or a neat Alternate Universe fic. Instead I find more horrible self-inset Mary Sue fics about OC/Goku. I seriously cannot take anymore of the 'Saiyan-girl who was on another planet when Frieza blew it up and found out how to go SSJ 10' story. It's so irritating, just like Mary-sues in general, anyways. In honesty, the only Saiyan OC I ever liked was DarthGlacier's, mostly because she's reasonable in terms of power, and has a LIKABLE personality. Other than that, Saiyan-sues make me gag.
So why am I bringing up this over-used topic? I'd like to take a few out of my time to send a message to fans about GOOD writing, and how to make a believable OC, because, as evident by the shit-ton of crappy Fanfics out there, SOMEONE'S got to.
Let's start by Character design. ALWAYS THINK REALISTICALLY. A pink and purple-haired Saiyan chick with a flower tank-top, Ambercrombie skinny jeans and a magic necklace that shoot lasers just isn't gonna fit in the Dragonball universe. Try a battle jacket, just like the rest of Lord Frieza's army. Or, if she's a hero, a training Gi in your choice of color, or a simple outfit, like Android 18. If you need more than two sentences to describe your characters outfit you've gone too far. Besides, you focus the spotlight on your character too much doing that anyways. (More on that later.)
Your Saiyan girl also has to be, well... A Saiyan. She needs black hair if she's a pure-blood Saiyan, and if she's part of the Brief's family, restrict the only other optional colors to blue and purple, no matter how tempting it may be. She also needs that lust of battle, to the point of an addiction to punching people's faces in, and if she's a pure-blood, she needs the sadistic and stubborn nature they have. She's not gonna be Snow White 'friend-to-all-living-things' if she's pure Saiyan, and don't even THINK about conking her on the head and making her lose her evil nature. It's just not original, it's cheap, and will honestly make your audience roll their eyes and say "Of course....". If she isn't a Saiyan, give yourself a pat on the back for being original, and the same should apply with personalities. Namekians should be asexual, Icejins are going to have a sense of coldness and cruelty to them, and humans are going to be totally useless. (Just kidding.)
Next, lets go with his/her sense of importance to the story. PLEASE, REFRAIN FROM GOING OVER-THE-TOP. The main character should be Goku or Gohan, or if she's a baddie, the main Bad Guy of the Saga you're focusing on. You can have some moments to let your OC shine and, more importantly, develop, but no one wants to read an "It's all about ME!" story about your character hogging all the glory and action. It's all about having a sense of balance. She also shouldn't be God-like in power, for the same exact reason. Her relationships with the others should be reasonable as well. Vegeta isn't gonna go ga-ga over her, Goku isn't gonna be suave around her, and Frieza isn't gonna be a sweet-heart. In fact, romance should take time to blossom. No-ones gonna buy a Love-at-first-sight- story.
You also need to be well-balanced about your characters powers and techniques. If she goes training with Frieza or Piccolo, she isn't gonna just pick up all the moves without breaking a sweat. Nobody's perfect, unless of course you're Cell. It took Gohan months to learn all of the fighting techniques that Piccolo taught him. It should be no different with your character. Show her struggling, and again, DEVELOPING. (Gohan went from whiny toddler who was dependent on Goku to a brave and courageous little kid who fought to defend his friends, for example.) Don't give her everyone's moves, either, unless, AGAIN, you're Cell. Nobody likes a copycat. Try to have a sense of balance on her movepool.
Finally, try to be original. Don't copy other character's discovery of new powers or characters roles. And PLEASE don't re-color. That's not cool. You want to make your OC stand out in a GOOD way.
Hopefully people learn to pick up these things when writing fanfiction, because a likable OC isn't impossible, I've seen it. Peace out, all hail Frieza.