PLD is such a fun job to play in a traditional xp party. I enjoyed it so much on retail and really wanted to relive it here but it got side tracked by many other things and is still on my 'to-do' list.
The sad thing about Nasomi is that you're going to be very hard pressed to find an xp party that does NOT have a PL. For me this completely ruins PLD and is part of the reason why mine is still lvl 20. I know you can make your own party and stipulate that you don't want a PL but with the server being as quiet as it is and with other groups plowing through mobs b/c they have 1, 2 or 3 PLs, it's not the easiest sell for other pt members. I see more PLD now that are using Great Swords in a party to bring some extra damage and there's no focus on damage mitigation.
With all of that being said, one thing that I think is very important and helpful to be a good PLD is to always come to a party prepared. I would highly encourage you to level up cooking to 60 so you can make Yagudo drinks, they are fairly cheap to make (all things considered) and if you can avoid resting for as long as possible you, and everyone in the party, will be very happy. If not 60, you can take cooking to 30 and make Pineapple Juice. Cooking is very cheap to level and you'll never regret being able to make yag drinks. The other nice thing about them is that you wont feel the need to equip something like an Astral Ring, which probably wouldn't come into the equation unless you're Galka but still, it's good to avoid -HP gear if at all possible. If you're into crafting, take up alchemy a bit and make your own echo drops, you can't do much of anything if you can't cast a spell and you don't want to HAVE to have a WHM in every party.
I do think that HQ gear makes a difference, if you're actually blood tanking and not just another DD in the party.
I'm not overly qualified to go into the details of ja/spell rotation because my first job to 75 was NIN and therefore I didn't see any PLD in the parties I was in.
There's more but it's time for work!