When creating a character, it's important to keep a few things in mind. I'm only going to cover two of these, but these aren't only two important parts.

First, and a point that often gets missed, is a well-defined core identity for your character, or, as I like to call it, the character's fantasy. This is what you want most of all out of your character, and is the last thing that you will give up for them: you're willing to let everything else about your character change before this pillar. That's how you know what the fantasy of the character is, and it's important to focus on this when creating the character.

For example, let us imagine that you're creating a character, and you decide "I want my character to be a stealthy ninja who can see the future and can electrocute people with his ENERGY EYES." I hope that you read that and go "hmmmmmmm, okay?" because that's purposefully an idea of a BAD character. This character doesn't have a clearly-defined fantasy, or one thing that we're supposed to focus on. Imagine if you were allowed to play such a character: in order to be balanced, he would have to be a stealthy ninja only from 12:30 to 1:00, only able to see 5 seconds into the future, and only able to give people slight zaps with his ENERGY EYES, because otherwise he would be completely imbalanced. No one wants to play with or against a character that is indestructible (can see the future), can do whatever he likes (is stealthy) and can unleash debilitating attacks from far away (ENERGY EYES). Without all of the "and"s, and proper counterplay introduced, then such a character would be acceptable.

So let's get rid of "and"s. What do you want from this character? Is the stealthy ninja what's important? Being able to tell the future? ENERGY EYES? Something else entirely that you were going to spring on people later down the road? Pick ONE. That's all you get: now build your awesomesauce character around this pillar. Now he can be the stealthiest ninja, or the most wise fortune teller, or Cyclops, and you have a fantasy to play.

The second point, I already mentioned: counterplay. Let's imagine that you decided that ENERGY EYES were super important to you, and you made Dirk, the master of ENERGY EYES. He's able to unleash an unstoppable laser of electricity at whatever he looks at, and it becomes stunned instantly and completely destroyed in a second. Pretty cool, right? We even named him Dirk because it has something to do with ENERGY EYES (hypothetically).

Well good job, he's nice and cohesive. I like how you tied his lore into his super power and he's cooler than a fridge. But... he's Overpowered. Imagine playing against Dirk for a moment: you are the Evil Badguy, and Dirk has come to stop you for Justice and Energy Drinks. You laugh diabolically as he mows through your minions and decide to wait to nuke the Red Bull facilities until he gets there to witness it, since Dirk once made fun of you in third grade. And then Dirk enters the room, and you attack each other... but wait, as you try to do ANYTHING he looks at you and you're stunned and then you die. The end. Why, in order to do anything against Dirk, you'd have to be immortal, or made of metal, or have the world's strongest Plot Armor. And if you do manage to subdue him, you better believe that in the OOC the Creator of Dirk is complaining about how it makes no sense because you should have been stunned and then destroyed, and he feels cheated, and the GM feels frazzled because he had to fight Dirk and the Creator of Dirk, and everyone else is bored because all of their characters haven't gotten to do anything because Dirk has done everything by looking at it.

See how that's just not fun? This is why Balance, with a capital 'B', is so important. You want Dirk to be a cool guy with a cohesive design who has some nice powers, but has to group with some other cool guys to destroy Evil Badguy because Evil Badguy actually puts up a challenge. If you aren't looking for that, then RPing isn't for you: go write some fanfic or something. RPing is about the group, and that means that everyone on the group should be on about-equal footing.

So how do we achieve balance while keeping Dirk's awesomeness in tact? Counterplay is the answer. Counterplay is the way that a hypothetical enemy can exploit your weaknesses in order to bring about your defeat: you have it, your buddy George (master of Sneaky Ninja Things) has it, and Evil Badguy has it. George can be defeated if you turn on a blacklight, because then his stealth doesn't work... oh, and he's also super weak when he's not stealthed, AND he can only be stealthed for like a minute at a time, and then needs a break. But when he is stealthed, and the enemy doesn't have a blacklight, George kicks major butt! Evil Badguy is allergic to cheese and has a weakspot on his back.

These weaknesses and disclaimers make these characters fun to play against, because they have weaknesses that can be exploited to defeat them. They're fun to play, because their weaknesses mean that they can have strong powers when their weaknesses aren't exploited. It's your job to do this with Dirk.

Now, that's not to say that counterplay is the answer to all things balance: for instance, you could have a character who can one-shot the world but he has to channel for a minute and he dies if someone sneezes on him, and that's STILL NOT FUN TO PLAY AGAINST (or as). It's important to keep in mind that key point: you want to create a character who is not oppressive to play against. If you can create a character with a power that people won't conceivably argue about the use of (and which is still fun for you to use), then you've hit the nail on the head.

Perhaps Dirk has a 1-minute cooldown on his laser sight? Perhaps it only stuns people at range, and he has to get in close for it to destroy them? There are lots of ways to trim back power while keeping the fantasy alive, and if you're in a situation where your power can't get any weaker and still be fun, then there's still hope: before you scrap it, consider if there's counterplay that you can add elsewhere that lets the power be okay with everyone. Maybe your ENERGY EYES can incinerate from close range, and the cooldown is a minute, but it's still not fun to play against, since if you stun someone all you have to do is get close to destroy them. Maybe add new counterplay: if you take 15% of your health in damage, you lose concentration and your ENERGY EYES go on cooldown! Suddenly, the enemy can survive if their minions attack you, and a team of enemy players can use teamwork to stop you from killing their poor medic. That can be fun!

Get all that down, and you'll be cranking out fun characters and you'll never have to see another person go "I think your character is stupid" ever again! Yaaaaayyyyy!