Equip the Offering and the Genji Gloves on a single character. You will be able to attack eight times in a row. Seems almost unfair doesn't it? However, it was also unfair that Kefka rearranged the goddess statues... mwa ha ha!
Secret Characters:
Mog & Umaro
Ok, first, go to Narshe. Bring only three people in your party. Open up the secret entrance that Locke showed Terra earlier in the game and go on in. Head straight through until you get to the room where Terra fell through the floor when the guards were chasing her. Once there, you'll see a door to the left of where she fell... go in. Follow the path and you'll come to a place where all the moogles used to live. Talk to Mog. He'll join you. Mog will tell you that he knows a saquatch (or yeti on the new version) in the caves of Narshe. Head up past the town (the way the party went when they were defending Tritoch)... you'll be able to fight an Ice Dragon on those fields... one of the 8 dragons. Then head on up north... fight Tritoch (fire spells take him out easy). Go through the opening in the ground once he's defeated. Explore the cave there and eventually, you'll reach a small dwelling. Walk up to the bone staff in the middle of the room and take the Esper Terrato. You'll have to fight Umaro. He's easy with fire magic. After you defeat him, if you have Mog in your party, he'll join you.
Gogo
To get Gogo, head for the triangle shaped island on the northeast corner of the map. There, you will ecounter a beast which people say can swallow oceans. Let it "engulf" all of your party and you'll be transported to a cave. At the end of the cave, Gogo waits for you. Don't forget to pick up all the treasures while you're in the cave because there are powerful items in there.
Shadow
After the big scene occurs on the floating continent with Kefka rearranging the statues of magic, you'll have a time limit to reach the edge of the continent and escape. Once you reach the edge, instead of jumping, choose to wait. Wait until there is about five seconds left and Shadow will appear and jump to the airship with you. This is REQUIRED in order to get Shadow. If you do not wait, he will die with the continent. Once in the WoR, go to the cave of the veldt. Explore the cave. You need to find two things. First, 'The Striker' a knife that Shadow came into this cave to find. Then, keep going until you reach the end, where Shadow seems to be lying unconscious (if Shadow dies on the continent, Relm will be here instead). You'll fight a beast. Defeat him and you will go to a scene with Shadow in bed. Leave that scene. Go to the colosseum and bet the Striker. Shadow will challenge you for it and then join your party... permenately.
Defeat Wrexsoul:
In Cyan's Dream, you'll fight a boss called Wrexsoul. There are two ways to defeat him. First, you can lower all of your party's HP until their all critical and he'll appear... then you can attack him. Or two, you can just use X-Zone at the beginning of the battle. Two things can happen here. You'll either A) suck the invisible Wrexsoul into another demension and win, or B) you'll kill both of his flusies and he'll appear by himself so you'll be able to attack him.
Leveling Up Tips:
The best place to level is a forest that is north of the veldt. It's a small patch of forest next to water. You'll run into T-Rex's and Bracheosauruses. Be forewarned that if you have just come from the floating continent and want to fight here, it is extremely dangerous. The best way to level here is to fight just outside of the forest at first. You can fight enemies that give a decent amount of experience, but are quite a bit easier. You'll fight some tumble weed looking creatures that can be easily defeated with fire, so it's good to start building up a magic using character, like Terra for example. You can level a lot faster by only leveling one character at a time. A good way to go about that is to use the mult-attack technique listed above.
How to get the Econimizer:
The econimizer is a relic that reduces mp costs of all spells to one. That's right, one mp to cast cure 3, ultima, and other favorite spells. When you fight Bracheosauruses in the forest talked about above, there is a small chance that it will leave one behind. A very small chance. And don't try to steal one with Locke... it doesn't work. You can only recieve it after a victory.
How to get the Moogle Charm:
When you get Mog to join your party in the WoR, he'll move from his standing spot to join you. Walk up to the wall where he was standing and search. You'll find the Moogle Charm, which, when equipped on Mog, enables you to walk around with a zero enemy encounter rate.
FOR CHEATERS-- How to get 255 of every item:
This is a bug in the program. It can only be done in the world of ruin and you need to make sure you have a lot of the legendary weapons and armor you can get in the game for the full effect of this bug. As far as I experimented with it, this works everytime, but only if you have the original game. If you're using an emulator, this will most likely not work.
Go to the Cave of the Veldt with Relm and Gau in your party. I have gotten this to work with just Relm, or Relm and Straggo, but Relm and Gau will work as well as anything. Once inside the cave, get into a fight. Have Gau go into one of his rages and then have Relm try to sketch him. Ok, now don't freak out because your screen will start to mess up. Your game will be fine, don't worry about it. Now, you need to exit the Cave of the Veldt and save your game. Reset your SNES and go back into the same game. You should see 255 of every item now in your inventory.
If this doesn't work for you, don't start E-mailing me complaining. Just follow directions more carefully or try again. I wrote this from what knowledge I had when I discovered it playing one time, but I think I remember it clearly, so it should work anyway.