Quick Kill
Equip the Cat Nip accessory and use the Trigger Happy ability when the wearer of Cat Nip has their health below half. You know this happens when their HP indicator turns yellow. The Cat Nip accessory allows any item, attack or spell to deal 9999 damage no matter what the circumstances. Since Trigger Happy allows you anywhere from 10 - 20 hits depending on what level you have it at, you can pretty much kill any enemy in the game using this strategy. Just remember, enemies are also affected by this too!

Extra Ending
First you'll have to meet with Maechen at Guadosalam in Chapter 3. You'll find him when you meet up with Logos and Ormi in the same area. Next you have to get the "whistling" scene with Yuna at the end of Chapter 3. When you're alone in the Farplane, move Yuna around and continually press the X button. You'll hear whistling. That means you have activated the event. Next thing you have to do is get an Episode Complete in Luca during Chapter 5. All you have to do there is visit the location where Tidus taught Yuna how to whistle. Next, get an Episode Complete in Besaid. Finally, once you have defeated Shuyin at the end of the game, keep tapping the X button to get your just rewards!

Level Up!
Good places to level up during the game are the Leblanc Syndicate's headquarters early in the game, Cid's secret dungeon during Chapter 5 for mid level characters, and the Depths of the Farplane for high level characters.

Quick Fix
If an enemy hits you with Stop, cast Haste or use a Chocobo feather on them. They'll be back to normal, and they will also have Haste cast on them.

Easy Healing
If you need to heal up, change your characters into White Mages, because they have the lowest HP in the game. You can use regular Potions or low level white magic spells to cure them. Revert them back to their original classes and they'll be at max health.

Get Baralai's Sphere
Baralai's Sphere can be found in Guadosalam beyond the locked door that everyone talks about. How do you do it? Examine the door in very Chapter. During Chapter 5, Tromell Guado will let you inside, if you were able to finish the mission on Mount Gagazet during Chapter 3.

Easy Money

After giving O'aka 100,000 Gil to pay off his debt, he will sell you items for extremely cheap prices. He sells Hi-Potions for 50 Gil, but you can still sell them for normal price. If you buy 99 Hi-Potions at the 50 Gil price, and then sell them all, you can make over 3 times the money back. You can do this process over and over until you have the desired amount needed.

What is New Game+?
New Game+ allows you to start the game with all of your Dresspheres, Garment Grids, Items and Accessories from your previous game. It also starts you off with the Story percentage that you ended your previous game with. In fact, the only thing you don't get is your levels. You'll have to earn those all over again. Using New Game+ is in fact the only way to get 100% in the game.

How do I use the Special Dresspheres?
In order to use the Special Dresspheres, you'll have to activate all of the paths on your Garment Grid. You can tell that a path has been activated because it will glow blue instead of the normal grey color. Once you have activated all of the paths on your Garment Grid, simply press R1 and then the X button to activate your Special Dressphere. Obviously, being able to activate this is much easier if you don't have a lot of paths to activate on your Garment Grid. This is why you can use the Unerring Path Garment Grid for quick access to your Special Dressphere.

I heard there's an extra ending to the game, how do I get it?
First you'll have to meet with Maechen at Guadosalam in Chapter 3. You'll find him when you meet up with Logos and Ormi in the same area. Next you have to get the "whistling" scene with Yuna at the end of Chapter 3. When you're alone in the Farplane, move Yuna around and continually press the X button. You'll hear whistling. That means you have activated the event. Next thing you have to do is get an Episode Complete in Luca during Chapter 5. All you have to do there is visit the location where Tidus taught Yuna how to whistle. Next, get an Episode Complete in Besaid. Finally, once you have defeated Shuyin at the end of the game, keep tapping the X button to get your just rewards!

What are the best Dresspheres to use?
There are Dresspheres that are useful depending on the situation you're in. In terms of pure attacking power, nothing can come close to the Dark Knight class. They have the highest attacking power and defensive rating, although they are slow to attack.

The best supporting class in the early going is the Songstress, mainly for the Darkness Dance and other debilitating dances the class will gain later on. However, later on in the game it becomes less effective. Of course, the White Mage is also very useful for healing characters and enhancing their abilities. However, the main drawback is that they can't attack at all.