First things first, a lot of people like to build the Limit Break (LB) Gauge during phase one so that they can ensure you make it past phase 4. If you have to rely on the limit break, you may be best finding a group with a bit more DPS to ease up the final phase of the fight. If your group asks you to aa (Auto-Attack) or build LB, you're going to end up auto-attacking until the bar is halfway full, until then you may start doing burst DPS. (What I mean is doing as much damage as possible). Now that that's out of the way it's time to move on to the big stuff.
Titan uses the same moveset every single battle, the only thing that changes is who he decides to target with landslide, gaols, and weight of the land.
Here's a comprehensive rotation: Phase 1:
Landslide > Tumolt(This is the name of his stomp attack. For ease of access, I'll simply call it stomp from now on) > Landslide > Stomp > Geocrush(From this point on I'll simply refer to this as Jump)
Weight of the Land>Landslide>Stomp>Weight of the Land>Landslide>Jump
Geocrush >Landslide>Weight of the Land>Bombs>Landslide>Weight of the Land > Gaol>Stomp>Landslide>Weight of the Land>Bombs>Landslide>Weight of the Land> Gaol>Stomp>Landslide>Jump
Phase 4: The heart
Stomp>Gaol>Landslide>Weight of the Land>Stomp> Gaol>Land slide> Weight of the Land >Jump(but not Geocrush, this time he uses Earthen fury. Depending on if you destroyed the heart or not this will either wipe your entire party or do massive damage)
Phase 5: Wrapping up
Mountain Buster>Stomp>Weight of the Land>Bombs>Landslide>Weight of the Land>Gaol>Landslide
Here is a list of what each attack does:
Tumolt(stomp): This is a massive AOE that is unavoidable. You're going to take damage no matter what, make sure your healers are capable enough to group heal you during these to keep you from dying, especially in phase 5.
Geocrush(Jump): This is another unavoidable AOE. You're going to want to group together as close to the edge (within) the red circle as possible. Do not step into or outside the red circle or you will fall off the edge unable to be rez'd. Stay together to get group heals.
Landslide: A rectangular AOE. This move is very easily dodged and you should always do it or you'll risk the chance of getting thrown off of the edge. In phase 5 when the bombs drop make sure you move to the center bombs, then left or right to avoid landslide. The first set of bombs (still in phase 5) will always explode in sync with Landslide. In phase 3 right after the bombs explode he will move into landslide, so always be ready.
Gaol: He will use this attack from Phase 3 and on. This traps a party member in a rock coffin. If he does geocrush or Earthen Fury then it will auto-kill that player, break these out as soon as possible. In phase 4 he will trap two people, save the 1st and ignore the 2nd until the heart is downed.