playing the psx version for the first time

I'm playing the PSX version of this game for the very first time. I've already figured that an easy way to gain JP and level up new party members is to just push the character to learn the Squire skill "Accumulate" and therefore gain copious amounts of JP by simply sitting a party in a random encounter with just 1 or two monsters left doing nothing but use that skill and if they don't have that then set those who can use it and have auto potion near to them so the ones in need can attack my own party to gain exp and jp whilst doing no major harm to the flow of battle. I'm just at the start of chapter 2 having gotten Ramza and several of my other party members to level 20 (the mission against Algus at the end of chapter 1 was seriously whopping my ass so I went and levelled up both my white and black mages as black+white mages with raise, raise 2 and cures 1 2 and 3 each I also gave my knights auto potion and hi potion from the chemist move list so that when it came to that I could for all intensive purposes walk through the fight without challenge. However what other tips/hints would you give me to follow? What job classes do you think I should aim to have in my party and if not the classes what particular skills should I go learn from jobs?

The PSX version is underated. While the translation is lackluster, it is much easier to aquire all the skills and rare items. Winning the game is moderately difficult, mastering it is is very challenging.

Some suggestions:

1) Accumulate is the best way to level up generic units, but most nongeneric unit do not have Basic Skills. The best way for them is to equip the Thief's Steal Gil. Hitting a unit from behind, they almost never miss and you increase your lucre at the same time. The other requirement is Gained JP Up. Don't ever bother with Gained Exp Up, since if you master every profession you'll max your levels long before you max you jobs.

2) In random battles the foes stay at commensurate levels to your own party, but in boss fights they stay at fixed levels, so you can always level grind your party to deal with difficult fights. You can almost always muscle your way through a boss fight, although in most cases there are specific strategies for winning.

3) The shops update their stock every time you advance the plot. It's important to keep at least your active party equipped with the best protective gear. Once your best armor is becoming ineffective against random foes, it's time to advance the story.

4) Generally the best job class for nongenerics is their own basic class, although with Mustadio can be an Engineer/Chemist or Chemist/Engineer either way. It's fine to have Agrias use Equip Sword when training in other classes, but once you get access to Knight Swords, you'll want to keep her as a Holy Knight, at least for boss fights.

5) There are many classes that have strength and weaknesses, but I feel the best generic class is Calculator. Or more specifically, Math Skills (the stats on the class itself are terrible). Math Skill allow you to cast almost all the spells of the White Mage, Black Mage, Oracle, and Time Mage instantly with no MP cost. It take time to work out the best claculation that benfits the party and damages the enemy, but once you, it's lethel. Once your party is level 99, you can always calculate against Level and multiple of 3 to hit the party and some other multiple to miss. It's my secondary skill set of choice.

6) Mediators will be absolutely necessary if you want to recruit monsters. And to be heartless, some of the rare items can only be gained by poaching your own monsters. In the end, there are terrific monsters that can deal tremendous damage to foes, although they are not as versitile as human units. My favorite monster are the three-headed Tiamats.

Gained JP Up should be one of the first things you learn for every character.

While the Calculator skill is easily the best in the game, in the meantime as long as your party is balanced with physical and magical characters, you should be fine. FFT is not so difficult that you cannot be successful with most combinations. I always would go for Monks first, and then eventually Ninjas and Samurai (Two Swords is the ability to learn from Ninjas to use for other physical classes). I would, even later in the game, have someone as a Black Wizard just because magic is badass. Just try everything out and stick with what you like.

I almost never used nongeneric units, with the occasional exceptions of Mustadio and later Orlandu. I always prefered crafting my own party from nothing.

Is it possible to recruit ultima demons, apandas or archaeo demons?

No, although you get to have Byblos monster join the party during the fight against (SPOILER)Serpentarius, and thereafter. Byblos looks like an Apanda, although it's skillset is slightly different.

Generics are must-haves for Propositions. More subtley, they actually change their appearance when they change jobs, so even though the roster is crowded by endgame, I always save space for one male and female generic.

Save often and be ready to just reset when you run into random encounters of lots of red chocobos.

I've never ended the game with any generics in my game, but that doesnt mean I dropped them right away when I got a story character either since I don't think all of them are worth it. Classes I'd recommend you spend time in mastering/learning several abilities would mainly be monk, thief (used to steal some of the best armor in the game later), and ninja. There are obviously nice things to have here and there but I tend to put most/all of my characters into these classes and may then send them to learn other classes individually (for instance just have a couple learn a ton of white magic instead of just a cure, esuna, and raise).

save after every battle, but keep four or five saves at different spots so you don't get stuck in a situation where you cannot win a fight and you cannot leave to go level up.

my advice are :

1. don't overlevel too much, because the enemies at story battle are at fixed level, so if your level too high, you'll be beating their ass without any resistance at all. My point is, there're no challenge if you're overleveled. Because FFT vanilla challenge lies on the first, second, and half of the third chapter. At the fourth chapter, i'm sure your level would be much higher than the story liner, for example my ramza at 78 while the last boss are no more than 50 cmiiw.

2. Define best job, the best job to kill multiple enemies at once is clearly calculator with their math skill. But keep in mind that calculator stats growth rate are horrible, so you wouldn't want spending lv on calculator, my advice is you should master calculator without gaining lv if possible.

3.About JP grinding, rather than wasting auto potion, i suggest you learn HP restore from Monk. this way you can hit your own party member without wasting any potion. just make sure the one you hit doesn't have COUNTER or any avoid abilities. and YELL is a must on grinding, go figure.

4.And another important thing, you should have at least 1 person with steal abilities at all battle. Better if you have 2, because there're a lot of battle which the enemies having great gear, not to mention (SPOILER)the rare perfume Chantage, Barette, Cacusha, Masamune, Genji set. good luck on getting the genji set from elmdor.

please consider my number 1 advice if you want this game to at least a little challenging. In my opinion, if you're not overleveling and not underleveling, chapter 1,2,3 difficulty are about 7/10, and the other chapter are about 4/10... so if you're overleveled, you wouldn't even have 7/10, maybe 5/10.