New tank looking for some tips to be a better tank!!

[Rongway]

Really, only Foresight and Bloodbath are considered essential. The others people take have their strengths and weaknesses:

• Protect (CNJ 8) - PLD's version of this skill isn't quite as good as the healers' version, as it only affects physical defense. But if someone needs to be raised mid-fight, and you have a few moments where you know you won't take heavy damage or be interrupted, you can hit it to give someone as a stop-gap until the healers can do you one better.
• Stoneskin (CNJ 34) - For a PLD, at endgame, this can become 2,000-2,500 HP mitigation that you might not have otherwise had. Downside is that you can't block or parry while you're casting, and it takes two GCDs to do, but it can provide a fair amount of additional mitigation. Depending on the fight, this can conceivably make it so that a healer's Regen can keep you topped off, outside of tankbusters. If you're offtanking, you can also throw it on the MT to help with tankbusters, or anyone who you know is about to hit with something.
• Mercy Stroke (MRD 26) - As a PLD, you're not generally going to do enough damage for it to give you the healing effect inside a dungeon, but when your soloing, it's pretty nice. It also provides an additional bit of DPS, as (I believe, but I'm not sure) it is off the global cooldown. NOTE: if I'm wrong and it is ON the global cooldown, it is a DPS loss for PLD.
• Fracture (MRD 6) - The main drawback of this ability is the fact that it's very expensive, costing 80 TP. However, until you get into Heavensward content, it does provide a bit of additional damage for PLD. Most PLDs don't take it, though, because in order for it to be fully effective, you can't clip the last DoT tick, and because we don't have any means to recover our own TP (and until the most recent patch, we were encountering issues where we were running out of TP).

Protect: Everyone's protect is the same as of 3.0. Take it and use it on un-dead party members to save the healers some MP/heal time.

Stoneskin: Use it as an extra cooldown, or better yet a cooldown-by-proxy when offtanking.

Fracture's total potency is 220.
Rage of Halone combo is 150 + 200 + 260 = 610 over three GCDs, mean potency 203.
Royal Authority is 150 + 200 + 350 = 700 over three GCDs, mean potency 233.
Goring Blade combo is 150 + 230 + 640 = 1020 over three GCDs, mean potency 340.
Skip fracture. It's overpriced in general and becomes even worse comparatively if you off tank.

Mercy Stroke is an oGCD 200 potency attack. Don't bank on its healing effect. You can't fire it often, and when you do, you'll almost never get the killshot with it because the timing is so strict, but it's extra damage with nothing to lose. Mostly take it because there's no reason to take Cure, Raise, Fracture, and Skull Sunder outside of raising people you run across on the overworld..

[Jpec07]

Fracture's total potency is 220.
Rage of Halone combo is 150 + 200 + 260 = 610 over three GCDs, mean potency 203.
Royal Authority is 150 + 200 + 350 = 700 over three GCDs, mean potency 233.
Goring Blade combo is 150 + 230 + 640 = 1020 over three GCDs, mean potency 340.
Skip fracture. It's overpriced in general and becomes even worse comparatively if you off tank.

Until you get Goring Blade (54), it still represents a DPS gain, as the potency per GCD is higher than your highest-potency combo (220 > 203).

The math is a little skewed when you get Goring Blade, because it becomes your highest potency combo even without the DoT in 3.2. The DoT's efficacy only counts if it runs at or near its full course, so if you're going for full DPS (which, OP, should only be done if you have a comfortable enmity lead in most content), the potency-per-GCD translates to roughly 150 (FB) + 230 (RB) + 240 (GB) + 150 (GB DoT - one tick per GCD) = 770/3 = 256.67 potency per GCD. So once you get Goring Blade, it becomes a DPS loss, but until that point, it still-potency's both Rage of Halone combo and Riot Blade combo.

I also need to confirm what you're saying about Protect. I could have sworn that the PLD version only buffed Physical Defense, but I may be wrong.