I guess I could write parts of it out and you can copy+paste whatever you think is appropriate... I don't feel like writing it in one big post because I know I'm gonna forget.
Baron:
Like the original trial, don't fight your opponent, because he will own you.
You do actually battle on the airship. There is no silly auto-battle where the main character decides to use items that are obtained late game. :P
Minor strangeness: After being "teleported out", you can run like the wind, and that kinda stops..
Pay attention to how enemies actually can rape you and can take some punishment. This means that you need to heal up (and save) early and often. Save money by using the Baron Chocobo forest instead of the Inn.
Level suggestion: James to level 8 or whenever Kain gains one level. I guess one could overlevel, but Cecil will never have decent enough Will to heal, so you're better off just buying potions for now.
Status lookout: Unlikely the original FF2/4, being devoid of a helmet, ring, or robe will provide no evade bonus, so it does you good to actually have something equipped. Also, Kain and Cecil's magic defense stats are... crap.
Boss: Mist Dragon behaves the same, so don't be retarded.
Post Mist disaster:
Try to save often and hold out long enough (try not to use items) before heading into Kaipo for Rydia's sequence. The levels will be beneficial when you have you level Rydia up.
Boss: They are stupidly easy, and fortunate for you, the leader of the pack don't run away... meaning free EXP!
Level suggestion: Rydia to level 10 (well, that's what I always do). Rydia's starting stats are a godsend, but she will still have to gain enough levels for a second attack because Cover only automatically works when less than 1/4 of a character's HP is remaining.. so you have to be really weary of her current HP.
Rydia's starting weapon is useless when the enemies HP is beefed.. so consider liberally using Chocobo so she isn't useless. Level 1 elementals not as useful since you must take advantage of an elemental weakness, and they won't kill on the first go.
Wanderers drop a nice weapon upgrade, if you want a nice STR boost to increase your attack multiplier.
Kaipo's equipment is a god send for Cecil. Decide whether you prefer trading defense for magic defense (I'm usually pro magic defense over defense) or defense for evade.
Wooden Staff targets the enemy.. but doesn't do anything that I can tell...
Getting Tella is not a bonus, but just another body to take hits. The best thing he provides is a healing staff, which is definately worth using virtually every turn so Rydia can focus on casting magic. Tella's starting magic is still the same, but his tweaked MP makes him even more useless, not that it wasn't already the case. You only need him to do two things anyways.. heal, or do one major attack.
The elemental rods you pick up are still useless, but if you need the extra magic boost, then go for it. The Thunder Rod is the strongest of the bunch, but that's not saying very much.
Magic: Warp has become a nifty spell. Remember the Molbol (FF2)/Marlboro (FF4)? Well, this spell does exactly what their bad breath attack does. The only issue is if the targets are resistant to one status attribute, it is immune to the attack.
Also, Rydia learns Toad at level 13... removing the need for CureToad.
Realize now that Cecil will never be the healer you want him to be.. other options will present themselves so take advantage of them.
There is one enemy in the Watery Cavern that plays the boss music. You can certainly run away, but if you know what you're doing, you just treat the enemy like if you were facing a boss... go all out.
Fear The Monsters: Minimages in huge groups are very annoying. The chance that someone will end up being paralyzed is pretty high, and that can prevent you from healing. Some of the attacks will include HP leakage, which can do a lot more damage than it normally does.
Boss: The 8-legged monster is still weak against the "Dark Knight's" weapory, so 2x damage is a good thing. However, those weapons are still useless against the Zombie that roam around the area.
The Berserk spell is still useful, but at a tradeoff... not that it should matter.
We have EVEN MORE themes now, but some old ones are gone...