Killing the Burning Oil above her is your highest priority. Control and cleave the trash mobs and utilize reflects and blocks while nuking her down. Destroy the gate after finishing her and gather on the other side of the wall.
If you are the first Weaver at the gate and still have Stealth, cast on the Burning Oil above Dulfy. At least one weaver should use on the mobs and Dulfy. You can use against the door for more damage. Use for better cleave.
Use from your Smokescale pet to stack Stealth at the beginning.
Use the smoke field from or (also useful for reflects) or simply cast to stack Stealth.
for for the multiple different projectiles knocking you down and occasional condition cleanse for Burning.
if neither of the aforementioned choices are relevant for your group.
The town
Again, stack Stealth and skip past all the mob groups. Plan ahead to not run into any obstacles. Gather after reaching the courtyard.
Note that there is a little jumping puzzle in case you are unlucky with barricades spawning, check out this video for reference. Using and also helps not aggroing the guards nearby. Watch out for the chicken that spawns there for an achievement (it is random if it's there or not), putting you in combat using the items, thus not being able to pull off the skip.
Use the smoke field from or or simply cast to stack Stealth.
To capture the courtyard, you have to kill (or kite away) four groups of Veteran Ascalonians.
As soon as you capture the courtyard, the Fire Caller will start a ritual and enemy groups spawn at the gates (clockwise starting north).
For more experienced groups it is favorable to take and go into the middle and casting for Stability against Knockback and Daze and for damage reduction.
The is very strong against the groups of mobs during the capture event. and prevent the enemy warriors Rush attack. Stay in before Ashym for Might stacking.
Captain Ashym
Stack Might while Captain Ashym runs towards you. Break his defiance bar as frequent as possible and be careful with his Meteor Shower AoE skill. He also tends to block multiple times during the fight, stop wasting your skills in that case.
Also pay attention to his boons as Resolution deals high damage to yourself. At 25% health, he will equip a Fiery Greatsword and gain additional skills, just make sure to end the fight quickly.