Tricks

Back Attacks

One trick that I found out is when you are attacked from behind don't just wait to be hit or to hit to get turned around. Instead of losing more HP than you normally would, just hold the run buttons, but not long enough to run away. When you let go of the buttons you should be facing your enemy.

Tetra Elemental

To get an accessory called the Tetra Elemental, which absorbs all Lightning, Fire, Water, and Earth attacks, fly the Highwind south of the Gongonga Reactor town to an uncharted island. When you land walk around until you fight an enemy which looks like a cactus. Keep using morph on him until he is morphed into the Tetra Elemental.

The Nibelheim Safe

When you go to the Nibelheim Mansion to find Sephiroth, you will find a letter that gives you hints to what the combination of the safe in the mansion is. The combination to the safe is: R. 36, L. 10, R. 59, R. 97.

Item Duplication

With the W-Item that you find when you go underground in Midgar after you parachute in you can duplicate items. To do this equip the W-Item materia then get into a battle. In the battle select the W-Item option, then select the item that you want to duplicate and select the character to use it on. Now, when you able to choose a second item select the same item. After you select it cancel using that item. Then when you are going to pick the second item again there should be another one of the item you first chose.

7777 Fever

Once one of your allies' HP reaches 7777 that character will attack until all of your enemies are killed. If you equip your materia just right then you can make it where your max HP is always 7777. The only bad thing is after you use 7777 fever your HP will go down to one.

7777 As Max HP

So far I've only figured out how to do this for Cloud so here's how its done. First you need to make sure you have the following materia:
FullCure - Lv.2
Alexander - Lv.1
Knights of the Round - Lv.2
Final Attack - Lv.3
Ramuh - Lv.4
W-Item - Lv.1
HP Plus - MASTER
Phoenix - Lv.4
Double Cut - MASTER
Even though I listed the level I had all of mine at, the only one that it really matters is the same level is the HP Plus. You also need to make sure your level is at or below 76 before you try this. The equipment I used was the Apocalypse sword and the Mystile armor(which probably doesn't make a difference but it is easy to organize the materia needed with this equipment). Now all that you have to do is get your level up to 76. If you set everything up right then you should have your Max HP as 7777. This helps a lot when trying to defeat Emerald Weapon.