The fastest way to do it in my eyes to around 270 was on the Pucks in Den of Rancor, but I didn't do it on THF. I had to use NIN to do it, but with 3 days of focus I capped it out. You're probably looking for a method that THF can employ and still get quicker rates, I've got to say it's not as easy as THF main due to the amount of damage you take if you went the same speed as a tankish type job.
I did NIN with DMG reduction gear, /BLU subjob, Tav Taco, and a RDM mule (with Phalanx II). I pulled a group of Pucks, targeted an enemy far away, and faced the group of pucks to get as many attacks against me as possible to raise the parry check frequency (I popped Innin to lower my evasion too). I noticed a huge difference between the rates when Martial Master was active and when it wasn't.
I haven't got mine capped at 80 yet like some people, but I've heard of a few enemy types post-75 (269 base) that seem to work well.
Zentoo on my server did a parry recap and recommended this...
To answer some questions, most of the skill-up have been done using sam/dnc (75 -> 269, 80 -> 294)
235+ : Jugner Forest [S] -> Decrepit Gnole
250+ : Al'Taieu -> Om'phuabo
269+ : Vunkerl Inlet [S] -> Gigas Marine/Deckhand
275->294 : Beaucedine Glacier [S] -> Gigas Cleaver/Pounder
Gigas Mnk are nice because they don't hit too hard, take care of the Gigas War they can hit hard ^^
Mine is stuck at 270 base while I relevel BRD and RDM back into Mandau. I haven't been focusing on much else except for the other skills. I was trying to cap everything out again as I took them to 80.