Um, I guess there are some general no-nos I could discuss about avoiding, if you really wanna hear them. Here they are:
*NEVER end your character's first name with the letter 'S'.It makes it awkward to write possessive forms of the name.
*Don't name your hero Jack. It's waaay too common.
*Don't, if you are going to do this, make your character's name obviously about their personality. Like, if you have a female characetr who likes plants, don't name her Flower. Name her something more subtle such as Sage.
*Make sure the character name is appropriate for the time of birth. A girl in her thirties named Lexi doesn't make much sense, does it?
There you go. There's more, of course but those are just some simple basics. Hope they helped!

I've learned something interesting in English class. It's a writing guideline humans have unconciously used throughout history for their stories. You may or may not have heard of it, but Harry Potter, The Hunger Games, and The Lord of The Rings all folow this. I thought you guys might want to look at this. So, here's what it is...

The Hero's Journey Writing Guideline;
1. Status Quo: Normal life for our hero.
2. Call To Adventure: The hero is caught in some event that sets them on the path of their journey. Sometimes, the hero first refuses to go on the journey, but is later convinced that they need to. Refusal of the journey represents that the hero thinks that they “have it too good”, and don't want their life to change.
3. Assistance: The hero receives help from help from a higher power of some sort. Sometimes it's in the form of an item to help them conquer a future challenge, other times it's a lesson or boost in confidence.
4. Departure: Our hero leaves for the special world in which they will partake their journey. This leaving of their world represents leaving all that they know and care for behind, and facing immense changes in their life. From the moment they step forth from their world, their life will never be the same again.
5. Trials: A set of challenges await our hero, and they are conquered one by one with various ideals, traits, lessons, etc. that the hero has learned. If the assistance included an item, it might get used in this stage of the journey.
6. Approach: The hero is about to face their worst nightmare, the final challenge. What happens in the approach can be either a self-reflection, moments of self-doubt, a gathering of courage, preparation for the final trial, or a mix of the four.
7. Crisis: The final challenge is almost too much for the hero. They come very close to losing, but so does their challenge. Our hero is in the Belly of the Beast, the lowest section of the gaping pit. Things look really bad for them.
8. Treasure: Miraculously, the hero pulls through and defeats the challenge, often using the assistance they got at the beginning of their journey. They are rewarded with something of immense value, sometimes material, like a magic gemstone perhaps. It can also be a life lesson, an answer to a question, the defeat of a foe, or even the rescue of someone they love.
9. Result: What happens because they received the treasure. Wraps up loose ends in the special world, so that they may leave back for home.
10. Return: The hero leaves the special world back for their own. Usually reunites with those they left behind, whether they love each other or not.
11. New Life: The hero tries to return to the way they used to live. Still, things will never be the same again for them. How can they, after their adventure? Sometime the change is better for them, and help them along in life.
12. Upgraded Status Quo: Our hero gets used to living normally again, for the most part. But, they can always go on another adventure if they just receive a Call To Adventure...

There's a lot of different variations on this, and no story follows it in the exact same way, but this is the basic summation of it.

EDIT: Just a funny note. I tried the Mary-Sue/Gary-Stue Litumus test on my characters Dasher and Sparkle. It astounded me, the difference between them, because I consider them very similar. Dasher got an 8, and Sparkle got 24. Wowza, triple the Mary-Sue-ness.

Could someone post a link to a Pokémon FanFic that has nicely-done battle scenes? I've found I have trouble in that department. It's usually just, "You there, do this... Hah, good job. Uh-oh, watch out! Now do this! Hey, we've won, look at that." They get rather boring after a while. So, my tip would be to, uh, not do that.

The Final Battle by The Obsidian Wolf is an entire fic devoted to a single battle. I enjoyed it when I read it way back and it was otherwise very well received.