How good...

[Maya]

...charachters should be when it´s wise to go to Highbridge?
I´m flying around Spira and tying to level up my party. I have dark aeons making things harder( I can´t pass them) too. My charachters aren´t yet very good. Still abilities to learn and hps aren´t that high.
Is it possible to beat sin etc. if you don´t have hp 9999 in every charachter and so on, like in some other ff games or do I have hours and hours training to do?

[sayen]

to beat sin you only need to do 9k with your magics thats it. you need holy and or ultima keep on casting it till sin gets close and use bahmuts armur breack and attack doing about 45 k of damage.

[yuna41269]

I defeated Sin with Auron having 4000 hp. While the others have 3000 hp. Strategy is important. I just taught Tidus Hastega, Auron with all the breaks, Lulu with DoubleCast, Flare and Ultima, Yuna with Doubleacast, Holy and Ultima. You must use the spheres that you are getting like Black Magic Spheres in order to teach Yuna Ultima. There are many ways.

[Maya]

I defeated Sin with Auron having 4000 hp. While the others have 3000 hp. Strategy is important. I just taught Tidus Hastega, Auron with all the breaks, Lulu with DoubleCast, Flare and Ultima, Yuna with Doubleacast, Holy and Ultima. You must use the spheres that you are getting like Black Magic Spheres in order to teach Yuna Ultima. There are many ways.

Where I can find those spheres???

[fire_of_avalon]

I can't remember where I picked them (the Black Magic spheres) up, but probably from some boss battle earlier in the game.

I beat Sin just a few days ago, and I didn't have Ultima. I just Hasteaga'd my party, then defended until Sin drew me close enough to melee. Then I used Armor Break, used Tidus's Energy Rain Overdrive, used Holy, did Mental Break, used Lulu's Flare Fury Overdrive, smacked him around a bit more with Auron and Tidus, then called Bahamut and he was super toast. But both Auron and Tidus were hitting close to 9999 at that point, and I don't know whether or not you're leveled that high.

[Maya]

I can't remember where I picked them (the Black Magic spheres) up, but probably from some boss battle earlier in the game.

I beat Sin just a few days ago, and I didn't have Ultima. I just Hasteaga'd my party, then defended until Sin drew me close enough to melee. Then I used Armor Break, used Tidus's Energy Rain Overdrive, used Holy, did Mental Break, used Lulu's Flare Fury Overdrive, smacked him around a bit more with Auron and Tidus, then called Bahamut and he was super toast. But both Auron and Tidus were hitting close to 9999 at that point, and I don't know whether or not you're leveled that high.

No not even close. Is there a good place to really train? Monster arena???

[fire_of_avalon]

I leveled in the Calm Lands, Mt. Gagazet, Zanarkand Ruins and the Omega Ruins, in that order. Whenever I would get too strong to level easily on one place, I'd move on to the next, and then just kind of run around and around until I leveled. If you have them, I'd equip weapons with double AP so leveling goes quicker. I did that because I'm impatient. :D

But that was after I got to Sin himself. Are you talking about the the battle with Seymour in Bevelle? I was MISERABLY under-leveled at that point in the game. So I ran around the Highbridge and would fight a battle, save, fight a battle, save, etc until I was strong enough.

[sayen]

the high brige the second time you dont have to fight and mika will send himselth you can train after wards i suggest finding the omaga ruins and traing till you can beat omaga and use lanct on him with kimari and you will get one of the best overdrives in the game supernova dose about 9999 damage with kimari having about 500 attack power.

[MoonZapdos]

...charachters should be when it´s wise to go to Highbridge?
I´m flying around Spira and tying to level up my party. I have dark aeons making things harder( I can´t pass them) too. My charachters aren´t yet very good. Still abilities to learn and hps aren´t that high.
Is it possible to beat sin etc. if you don´t have hp 9999 in every charachter and so on, like in some other ff games or do I have hours and hours training to do?

To beat Sin you need three things: Hastega, Anima and Magus Sisters
Nuff' said.

You don't need to train to have 9999 HP. Just get Ironclad at Monster Arena and overkill him for 2 HP Spheres.

Dark Aeons? You should only have problems against D. Yojimbo. Talking about Yojimbo... To beat a Dark Aeon (with lots of luck) you get 1.050.000 Gil, use Yojimbo a lot until he uses Zanmato/Wakisashi All at the start of the battle against level 1 zanmato enemies without paying and go face the dark aeon. First Strike helps. Summon Yojimbo, pay him 1.050.000 and pray. You have 50% of chance on using Zanmato and kill the motherf***er.

[Cuchulainn]

The % of Zanmoto only rises to 50 if you Grand Summon him. In regards to the Dark Aeons, saying 'only Dark Jimbo should be the only one to cause problems' when you haven't stat maxed is lies. They will kill you faster than someone on a grassy knowl. Once you stat max, Valefor to Shiva can all be beaten pretty easily with Auto-Haste & Quick Hit. Once you get to Jimbo you need that Auto-Life. Dark Jimbo is pretty easy I found, the hardest would definately be the Dark Sisters. For an easier fight, try & play the mini game when you run away from them, it can get annoying but if you split them up they become a hell of a lot easier & you don't see Delta Attack which will slaughter you, no matter how much you have stat maxed. Penance is immpossible until you adopt the right strategic, then he is easy as hell. Once you have to fight Penance, if you want help, post here & I'll show you my strat for killing him.

With regards to Sin, I remember that battle well, I found it pretty easy. I beat him before maxing my stats.
Firstly equip all the Stoneproof & Confuseproof Armours you have, modify if you need to.
Easy Win would be to have Rikku, Lulu & Wakka, get Rikku to mix 2 Wings to Discovery & blast away, he's be gone in no time.
If you failed to do the Remien Temple Chocobo Race and got 3 chests then it's Plan B.
Start wit Wakka, Tidus & Lu. Tidus Casts Hastaga, Lu pounds away with her lvl3 spells & Wakka attacks with physicals. If anyone has learned Holy, replace Wakka with them. After 3 'Drawn to Sin' replace Lu with Auron to Armour Break it. After that pound away, he'll be gone soon enough.

[Pouring Rain]

Which Sin? If it is Overdrive Sin, all you need is holy, one aeon, some eathers, doublecast, and Auron. Auron does all his Breaks. Lulu does doublecast flare or ultima. If you are unlucky like I was and didn't have Flare or Ultima, use Blizzaga. That was good. Anyway, use Wakka until Sin draws close enough so that everyone can attack. I had a disturbance so I couldn't think one of the times I fought Sin. "That's a rock!" "No its not, its a blitzball!" "There's no such thing!" "He's a survivor!". Family. You could do without them. Anyway, after Sin is close enough, use all your overdrives. It will help so much. Use one of your strongest aeons for the overkill if needed. The guidebook is wrong. The overdrive goes up if you use an aeons overdrive and thats why you use one for thr overkill. Throw 100,000 Gil to do 9,999 damage points. Yuna's Holy will do 9,105 points if you are leveled like I am. All your strongest players should have 4000 or more hp. Wakka, Auron, and Tidus were my stongest and everyone else had 3000 and something. 300 or more mp for Lulu and about 280 or more for Yuna. If you don't have their Celetial Weapons, Yuna will only have enough mp for about two Holy's. It costs 80 mp so use it wisely. I actally found it easier than Yunalesca. That's what I did. Hope it works for you...

[Maya]

I mean that point where you first go to Highbridge and then it leads to battle with Sin. Now I can travel all over the Spira before that.
Thanks everybody. I think I can go on with your help. I think I have made some mistakes earlier in the game, but nothing serious, I hope.
But still I don´t like dark aeons. They kill all in my party before I can do anything.