Any tips for a beginner tank (lvl 10-15)? Skill rotation? ways to keep enmity and apply it to mobs that spawn during an engagement?
Fast Blade > Savage Blade will always be your go-to combo for building hate on one enemy. You're kinda SOL when it comes to endgame people doing low level dungeons because they're simply gonna build more emnity than you can, even if you only do Fast Blade > Savage Blade over and over. This is why marking a kill order is important in the early, since its a lot easier for the tank to manage enmity if everyone is focusing on the same target.
Since you didn't specify if you were playing as Gladiator or Marauder, I'll include ideal rotations for keeping hate in the level range you mentioned (and assuming you have no cross-skills).
For Gladiator:
When pulling a group of enemies: Shield Lob on the first target > Flash > Fast Blade > Savage Blade > Flash. From there you can keep using Flash Blade > Savage Blade on whatever the current target is, using Flash on occasion to keep other enemies in check. Riot Blade can be used if you run low on MP, but you shouldn't abuse it since it costs a lot of TP to use. Remember that your job as a tank isn't to deal damage, its to keep enemies on you at all times.
For single enemy pulls, do the same as above but omit the flashes. Shield Lob and then spam Fast Blade > Savage Blade until it dies.
Your main rotation will change once you get Rage of Halone at lv 26. It's a 3rd attack for the Fast Blade > Savage Blade combo that generates a ton of enmity and puts a strength debuff on the target. The Halone combo will be your main enmity attack for pretty much the rest of the game.
An additional note: I see a lot of gladiators not understanding how Provoke works (not that I blame them, the description is pretty bad). Provoke will instantly put the user at the very top of the target's enmity list no matter how much hate it has on anything else. What this means is that, in the event that you lose hate on another target either because you died or a Black Mage/Bard/Dragoon got too greedy and drew too much hate, you can instantly recover and put yourself back as that enemy's main target. However, Provoke will only give you an additional point of enmity higher than whoever is at the top, so make sure to follow up a Provoke with another big enmity raising attack like Shield Lob, Savage Blade, Rage of Halone, etc.
Worthwhile cross-skills: Stoneskin (Lv.34 Conjurer) and... that's about it. Paladin cross-skills are kinda poop.
For Marauder:
Group of enemies: Tomahawk on the first target > Overpower to draw hate on all the other mobs (use 2x if needed) > Heavy Swing > Skull Sunder. Overpower is basically your equivalent to Flash, but it does some damage and eats a lot of your TP, so only use as needed. Brutal Swing allows you to Stun enemies and interrupt any casts that they'd be doing at the time, plus it's an Off-GCD skill meaning you can use it at any time regardless of the normal skill cooldown. Fracture does some additional damage over time, but you generally shouldn't need to use it if the DPS are doing a good enough job.
Single enemies: Tomahawk then Heavy Swing > Skull Sunder until its dead.
The rotation changes once you get Main at lv 18 and Butcher's Block at lv 30. The former combos' off of Heavy Swing and will temporarily boost your damage, the latter is a 3rd attack for the Heavy Swing > Skull Sunder combo that'll get you tons of enmity. That'll be your main single target enmity combo once you get it.
Necessary cross-skills: Provoke (Lv.22 Gladiator). Useful ones are Flash (Lv.8 Gladiator) doesn't give the same blind debuff as the Gladiator version, but still nice to have), Convalescence (Lv.10 Gladiator), Internal Release (Lv.12 Pugilist), Mantra (Lv.42 Pugilist)
