so what is the good way to level up? I'm tempted against my better judgement to play the game again someday
Well, I'd suggested to Sunblade, since he hasn't beaten the game before, to play the PSP version since everything levels up faster in that version. He chose the PS1 version, though, so he's had to deal with everything levelling up in a more balanced way as opposed to being a little easier on him.
The game truly is balanced enough to facilitate you doing everything naturally after the beginning. You just have to do a little bit of work at the beginning and then let it flow like a river. Let your hair down, etc.
The best thing to do is to
stop hitting yourself with one exception: when you get Minwu, cast Sap/Anti/Faze (same spell, just different name depending on the version) on Maria and Firion to increase their MP. Hitting yourself and leaving a rock on X or B is boring and it artificially inflates your play time. Don't do it. Leave everyone in the front row if you want their HP to increase that badly.
You don't even need to bother increasing MP with Guy; he's a hitter, he hits things. You can give him a spell if you'd like and increase his MP to 100 with Sap but I generally don't see a need to do it. His stats are not conducive to spellcasting to me, and I used to level up his MP and give him magic until I realized that his stats aren't for that at all.
So:
Firion: The most balanced guy. Magic stats are on par with physical stats so it's best to make him whatever you want. I go with making him like a paladin or something. I usually gave him swords and lances. The biggest risk to Firion, if you were raising him as a paladin in the NES version was that giving him a sword would destroy his Spirit stat (and his intelligence stat) since they lowered those stats by 50! Blood Sword lowers it by 100. That risk doesn't exist in the PS1 version and beyond, so it isn't problematic to do so. Giving him a lance in the NES version would lower it by 40 which isn't as bad as the 50 but it's still a dramatic drop.
Maria: The highest intelligence, the worst attack, the worst HP growth, the highest agility. She's the best out of the three suited to be a Black Mage-like character. I think it's kind of obvious as to where to take her here. I stuck her with Staves and Daggers. In the NES version, daggers and staves would give a -5 penalty to Intelligence/Spirit but that's WAY better than hte -70 that the bows take off. None of these penalties exist in the PS1 version and beyond, but I usually stuck to daggers and staves.
Guy: Highest strength, HP. Has high stamina. Has the lowest Agility stat (meaning that 95% of the time he'll take the last hit... and if you're a spellcaster you don't want super-low agility here). I guess if you wanted to give him spells, give him buffs that are unaffected by Spirit/Intelligence like Haste, Protect, Shell, etc. I don't know if I'd agree with that since he'd probably be the last character to complete an action during a round and you'd probably need the buff at the beginning of the round, but it's up to you. I usually stick him with Axes or barehanded.
Don't make everyone a jack of all trades. That's the worst thing you can do, since you'll be spending a ton of time levelling everything up instead of actually playing the game. And that's boring. Give everyone 1-2 weapons to concentrate on and that's it. No more otherwise you'll end up spending too much money on stuff you don't need and spending too much time levelling up weapons that you don't need to work with. I usually class everyone right at the beginning (ex: Firion is my paladin-like character, Maria's my Black Mage, and Guy is my monk; it's more effective that way, and it makes the game dramatically easier for me). Level up weapons to Lv 2 at the beginning. Some go to Lv 3 but you don't need to. If you're playing the GBA/PSP version, though, things will level up faster than expected, so I guess you'll have an easier time with it.
When you first start playing, just buy Fire/Ice (you could buy thunder but I don't see why you'd immediately need it since not a lot of enemies at the beginning are weak against it), Cure, Raise, Esuna, and get them to Level 2-3. I've seen people say get them to level 3 and then progress, but I don't feel like it's necessary in the GBA/PSP versions of the game. So after you level up your spells a little bit at the beginning, just play the game normally. The game's balanced enough that you don't need to grind things out or hit yourself. After that you don't have to worry about stats at all because you've classed everyone and the game's balanced appropriately to keep everyone in check since you're accustomed to using everything in a class-based way.
Play the Snowcraft minigame. There's a real good cheat out there on how to instawin every time and you'll get tons of money every time you play it (ex: play it once and write down where the cards are, when you're finished the game, say you want to play again, but then cancel the game. When it asks if you wanna quit, say no, and repeat cancel the game/no i don't want to quit options 31 times, and it'll reload the first game you play so you can redo the first board again). You can get some decent armour and some money from the game and it's easy enough to not have to do the cheat.
Could go to the swamp/peninsula of power near Finn and kill the enemies with magic to level some class-specific stuff up and get some cash. Use said cash to go to Mysidia to buy stuff. Then resume the game like normal. Don't have to hit yourself or grind anything after that.
And when all else fails just cast toad on everything after you get it, I guess.
I mean, SaGa/Legend of Legacy kinda uses the same levelling progression too, but with some tweaks, so that's why I'm used to it now. FF2's system is just a barebones version of it. I just hate grinding in any RPG since I feel like it wastes a lot of time, so I tried to make FF2 easier enough to prevent myself from doing it. Since it worked out for me and since it's worked out with Sunblade, I guess the method works provided you aren't playing the NES version. FF2 is just one of those games that gets better on nearly every re-release.
