10 Phoenix Downs and a Secret Cave:
On the way to Coral, go to the switch that you push to let the others go through. If you explore around that area, you should hear birds chirping. Go up the hill where you hear it (you might have to search to find the right spot) and pick the first choice you are given.
After collecting the 10 Phoenix Downs, go back down to the lower tracks and follow your partners. As they turn to the right, you need to take the left split because buried in the hill under the tracks is a cave with an out-of-work miner. A Power Source, Mind Source, and Tent may be acquired within this hidden area.
Note: Your score will be lowered if you do this. It's not nice to disturb baby birds.
To get to the Ancient Forest before disc 3, simply ride up the hill with a black, gold or green chocobo.
Beat the Cosmo Canyon Boss:
When you get to the Boss inside the caves at Cosmo Canyon to beat him all you do is use a Phoenix Down on him to kill him instantly. Sometimes that misses so you might want to use other healing items like X-Potion, High Potion or Potion.
Beat the Emerald Weapon:
If your having difficulty beating Emerald Weapon and you can't get the Knights of the Round consider using this method.First equip three gravity materia, one to each character, second if possible equip a mime materia to each character.
Next to one character, equip both the W-Magic materia and quadra magic materia joined to the characters gravity materia. Join an all materia to the other characters materia. Okay. Now when you go into battle all you do is use any level of demi on the Emerald weapon and it automatically does 9999 HP of damage to with every hit but at the end his HP will lower and a couple of hits with a moderately powerful summon spell and he's done for. Voila!
Beat the Ruby Weapon:
For this you will need Nights Of The Round with at least 3 levels. Phoenix summon with at least 3 levels. Shield with at least 2 levels. Final Attack with any level. About 3 mastered HP and MP pluses (you might need more). 3 Enemy Skills with White Wind learned (to learn White Wind, go to the grassy area of Junon untill you fight a big green creature with wings. Manipulate it and have it use White Wind on your party).
You also need MP and HP absorb and the MIME command. Make sure you do NOT have the w-item, w-magic, and w-summon materias. Give everyone HP pluses untill it reaches 9,999 HP. Then do the same with the MP pluses until it reaches 999. Equip Cloud with the Ultima Weapon and give him the following materia.
Combine the Nights Of The Round with the MP absorb. Give him Phoenix with Final Attack. Give him mime with HP absorb. Make sure that you only eqip these matiera on the Ultima Weapon if their mastered. Give him shield and enemy skill. Give your other party members the other enemy skills. Make sure Cloud has an accesory that will protect him from Frog and Small.
Before you fight Ruby, get into a battle and have Cloud kill your other party members. Now go after Ruby. Start off by using shield on Cloud. Do NOT have Cloud bring the rest back to life.
Now have Cloud use Knights of the Round and just keep miming it until the Ruby Weapon kills you. When you come back to life, repeat the process until you've won.
NOTE: No matter what, do not use any limit breaks or regular attacks on Ruby. If Cloud becomes a toad, use white wind to heal him.
Cast Any Spell Three Times:
To cast three magic spells in one round, first equip someone with a Magic Materia + "All" Support Materia. You'll also need Barrier Materia with the Reflect spell learned. When you enter battle, cast Reflect on the entire party, (your party). Then cast the magic spell that was connected to the "All" Materia on YOUR party.
Even though you cast the spell once, it will be reflected and returned to the enemy hitting for three times! And for the same price of the usual MP's. What's even better is that if you have W-Magic, you can cast that spell twice, or two different spells (both need to be connected to "All" Materia) hitting for six times!!!