Playing the international version makes gambits seem a lot more...necessary lol.

I find myself always having a WHM or RDM (Penelo or Vaan) in the main fights. I'm right outside of going to fran's homeland, so I am not too far. This is normally what I have set up though, along with the typical attack/heal gambits.

Gambits for healer:
[Ally:Tank -> Decoy]
[Ally:tank -> Protect]

(Do not use shell if using Decoy!!)

If the hunt/boss has a debuff its weak to, and I own it:

[Foe: Party leader's target ->Debuff]

For tank:

[self: (HP<60) -> Cure or something similar.

I do more here and there, but unfortunately, I'm very limited in my spells right now. I didn't choose BLM because I wrongly assumed that RDM got all the debuffs and low-tier elementals, which it does not. (dang FFXI LOGIC!)

You should also have some gambits for the reflect trick, like someone above previously stated.