Final Fantasy X - Tips
I. First and foremost, make sure Wakka has a part to play in EVERY battle; this will go a long way when you're looking to get his Overdrive Reels after you recruit Brother. Even if there is no aerial enemies for Wakka to kill but you have him in the battle to at least cast Aim that is good too because he'll still have participated in battle.
II. Get 10 Sphere Levels in the "long" areas such as Besaid Isle, Kilika Forest, Mi'ihen Highroad, Mushroom Rock Road, Djose Highroad, Thunder Plains, all of Macalania, Bikanel Isle, Calm Lands, Mt. Gagazet and Zanarkand Ruins.
III. Get 2-5 Sphere Levels in the "short" areas such as Moonflow, Bevelle and Via Purifico. You know what they say, every little bit goes a long way.
IV. Don't play Blitzball until you recruit Brother; that's very important.
V. Score Overkills by exploiting the personal strengths of your characters and the elemental weaknesses of your enemies.
VI. Your Blitzball dream team is:
Tidus - At the start
Zev Ronso - Luca Docks
Jumal - Luca Plaza
Ropp - Mi'ihen Highroad
Rin- Airship
Brother - Airship
*Recruit the latter 5 as you journey throughout Spira
VII. Brother is "recruitable" for Blitzball when you get aboard the Airship at Home in Bikanel Isle.
VIII. In Bevelle Cloister of Trials, make sure that the Sphere stand has two Bevelle Spheres by the time you reach the end because you'll be able to get the "non-destruction sphere item".
IX. When fighting Seymour Flux on Mt. Gagazet, cast Haste with Tidus then cast Bio with Lulu on Seymour Flux; you'll get nowhere trying to do this on the Mortichis.
X. When you're hunting for the Sigils and Crests for the Ultimate weapons, get the Sigils first because they are the hardest to obtain.
XI. When you revisit the Baaj Temple, you'll gain Geosgaeno's attention. Before the battle, customize stone ward/stoneproof unto some armor so you'll be guarded against its stone punch which is technically instant death.
Plus, make sure that your people have their Overdrive meters maxed out.
XII. Just before you take on the Magus Sisters under Belgemine's command at Remiem Temple, make sure every aeon is in max Overdrive status.
You must have Anima from the Baaj Temple ruins before attempting to get a piece of Belgemine.
XIII. Make sure that everyone in your party has armor that has Confuse, Berserk or Stone ward or proof before attempting the Omega Ruins
XIV. If and when you need teleport spheres so you can move your people around the sphere grid, capture a Master Tonberry from the Omega Ruins with a capture weapon so you can pummel it at the Calm Lands Monster Arena for 3600 Gil. This way, you can get all of the teleport spheres you want and need. Works better if you have all of the ultimate weapons because scoring an Overkill will increase the chances of scoring 2 teleport spheres after each kill.
XV. In need of Lv.4 key spheres, have Rikku use her Bribe ability on the Chimera Brains in the Calm Lands. It's recommended that you have near 900,000 Gil so you can bribe both Chimera Brains in battle, 200,000 Gil for both should suffice.
XVI. You'll encounter Behemoth King inside Sin, make sure everyone has learned Auto-Life beforehand; use it on your 3 chosen characters at the start of the battle to spare them Behemoth King's Meteor attack.