Hmmmm... I didn't just do one thing, so I'll try to properly explain it.
The game has 6 characters with a different class each.
Jack Hoth, The Hashassin, whose skills do damage based on Attack, Agility and Luck. With a focus on DoT effects.
Titties McBewbs, The Toasty Meister, whose skills do damage based on Magick Attack and Attack. Some of her skills cause herself power burn (a DoT).
Cutie Cake, The Fairy, who is the healer and has light based magick spells to do most of his damage.
THAT GUY!, The Marked Marksman whose skills do damage based on attack and agility.
Sidekick McNobody, The Meatshield, who has attack based damage, but most of his strong skills unbalance him so his Def gets reduced for 2-4 turns.
And McDoogle, The Wizzard, who starts with wind spells, and the player can buy a variety of others depending on how they want to spec him out. The most powerful damage dealing spells also cause him power burn.
Spells always do damage based on magic attack, so they also scale with level, like other skills.
So, out of the 6, only ones' skill damage is based only on attack, so he's the only one with a high attack stat.
I then made the baddies good and tough, and with powerful attacks of their own. If you don't find ways to bog them down and stop them from using their skills, they will stomp you.
The further into the game you go, the less basic attacks will damage. Even with the best weapons in the game, towards the end you wont do much damage that way. So you have to use your skills, or you will die.
You have to do crowd control, while setting up combos with debuffs and buffs, and getting your SP (instead of TP) up to use your best attacks. Spells do consistent, but not incredibly high damage. Unless you use the aforementioned spells, that also hurt the caster to use.
I also made it so most skills use both MP and SP.
The idea being to force the player to make cost-effect calls for every character, in every turn.
With the stats, I started at roughly the same level as the main character's baseline stats, then added a few points for each new enemy.
First enemy in the game is Bruce, and he has 200HP, 1MP, 22Atk, 14Def, 1Matk, 1Mdef, 14 agi, and 14 luk.
The final boss has 75,000HP, 785MP, 490Atk, 490Def, 490Matk, 455Def, 200Agi, and 200Luck.
Then I tweaked them based on whether or not they used spells. Made them stronger or weaker based on the numbers they'd be fighting with, so you don't end up fighting a group that are all as strong as the solo dude you just went up against.
Gave them any abilities I thought they should have, and playtested to see if I needed to tweak stats because of them.
At the end I playtested through the whole game to see how a player would have to deal with everything, and tweaked everything again as I went.
For example, I put money bags in that give a random amount of money, instead of flat drops. But about 4 areas in I felt I wasn't getting enough money, so I increased the amount each type of bag gives, and added in a couple of bigger ones.
I also felt it was way too hard to get weapons and armor, so I made everything cheaper and added extra drops.
Combat balance isn't just about enemy stats, it's also about the resources the player has to work with. I wasn't giving out enough cash to let a player stay stocked up on items, and buy new gear. So I increased the amount of money, made things more affordable, and made it more possible to get some gear from drops.
While it isn't a gear based game, those few extra stat points do make a difference.
For a game where gear is more important, it's just as important to make sure they can get it.