Mesmer PvE | Dungeon Sword/Focus, Greatsword | Damage Dungeon Meta Variation

Granted especially on mesmer, no weapons or skills fit every situation. Certain skills will suit certain fights/areas much better than others. Major ones of note though.

WEAPONS
Mainhand
Sword ; Best dps from auto attacks, especially versus multiple targets. Blurred Frenzy is also very useful.

Scepter ; Useful for places where you absolutely don't want to be in melee range, but Phantasmal Warden or PHantasmal Duelist are still good.

Offhand
Focus ; Very useful vs ranged enemies, and projectiles that must be blocked. There are just SO many situations that there are projectiles to block. You'll start noticing them as soon as you start paying attention, they come quickly more and more obvious.

Pistol ; In single target boss fights, where you need a phant that isn't in melee, but will be in melee or rotating in and out of, this guy is strong to make before you move in. Phantasmal Duelist works well with Sharper Images.

Twohand
Greatsword ; Generally useful weapon for most situations. More viable now that Spatial Surge is able to hit up to 3 foes in a line, going through to the last target. Mirror Blade and Phantasmal Berserker both hit for nice amounts of damage. Standard weapon when you DO NOT want to be in melee range. Mind Stab is also a good attack for some boon removal. Very useful vs long duration or high stack fights.

Staff ; Can be quite useful in condition heavy groups, also when you need a ranged phant, and a 1200 range auto attack. This is actually deceptively more powerful than it seems, with the allied bounces able to proc might/fury, especially on fury procs. Chaos Storm also offers great group support, along with another field.

SKILLS
Ether Feast/Signet of Ether : The IMPORTANT thing about Signet is that it refreshes your phant timers. If you are in a condition heavy fight, where you can make more use out of Mender's Purity, take Ether Feast instead. Also if you are in a fight, where illusions are constantly dying and you can't keep anything up, and are afraid of taking too much damage, again Ether Feast.

Most often switching to another utility skill will replace Portal Entre. Feedback is almost always useful for a field if nothing else, and Blink is a huge life saver.

Decoy ; Useful for retrieving items or stealthing past some enemies.
Feedback ; Useful vs any ranged projectiles. This is an almost always equipped skill.

Null Field ; Good for condition heavy fights that will hit your whole group. If more than one person has an AoE condi heal, try to coordinate if possible.

Veil ; Again for stealthing through areas.

Arcane Thievery ; There are a few fights where some bosses can pick up some pretty heavy boons. Knowing which those are is the key to using this skill.

Signet of Inspiration ; Nothing too special by itself, but when used with Arcane Thievery or with a party who is throwing down a lot of boons, the active can double up a nice set of boons.

Blink ; Stun break, instant movement. Also breaks knockdown/fear.

Illusion of Life ; This skill tends to be extremely clutch, I've found very few situations for this one. One notable high risk fight was the boss of the Grawl Fractal, since getting people up can be very difficult during little lava ele spawns.

Mantra of Concentration ; I haven't seen too many situations where this skill would make a LARGE difference. One extremely notable is vs Lupicus in Arah for getting out of the green sphere that bounces you back inside. This is our only source of stability.

Mantra of Distraction ; This is again, another very situation skill. It is normally very hard to use in PvE though due to Defiance stacks on champs. Can require some coordination in party if you want to actively interrupt boss skills.
Mantra of Resolve ; Very useful for condition heavy fights.

Phantasmal Disenchanter ; I would have never considered using this for condi removal before, but with the active on Signet, MAYBE there's some PvE use on it. Still though, blowing your heal and losing passive for that long to remove a condition is ehhhhhhhhhhhhh.

Signet of Illusions ; Always you can use your clones/phants as 'liquid' HP targets to eat dmg. This just makes them a little bit harder to kill, and can be quite valuable vs some bosses if it takes two shots instead of one shot to kill them.

Elite ::
Mass Invisibility ; Mainly useful for stealth runs.

Time Warp ; This should be the usual standard for PvE. Amazing damage increase for wrecking boss, getting things done.

Shatters :::
Not going to go into these too much, as I don't find them useful in dungeons for the most part. Distortion is the one difference, as it can be a huge lifesaver when used to revive a downed ally, or to avoid damage that would leave you downed yourself. Diversion is also very useful in a coordinated group, where you can stop a boss from casting certain skills, but this can be very hard to use with pugs due to defiance.

Dueling : This tree all stacks very well with itself. Pretty sure none of our other trees just work out this well.

Critical Infusion ; Keeps you alive, and provides more dodges for Deceptive Evasion.

Major Tier 1 ; Phantasmal Fury is always useful for adding Phantasm damage.
; Blade Training can also be used for trash mobs, or for any fights where you want to melee constantly and have more uptime on Blurred Frenzy

Sharper Images ; Just puts out more damage. Chance goes up with the base stat on tree.

Deceptive Evasion ; Creates a clone on dodge. Invaluable especially while using Signet of the Ether and Compounding Power.

Confusing Combatants ; My PERSONAL preference instead of shattering, normally involves leaving my clones/phants out until they die. This also procs on overcasts on illusions. Meaning if you have three up, and make another, the one that disappears counts as a 'death' and will proc the AoE confusion around itself.

Inspiration ;
This tree is mainly for dungeons and focus skills reflect. It has a few other things that help out with survivability though.

Vengeful Images ; Helps dish out a little bit of extra damage on your phantasms. Doesn't necessarily stand out IMO, but good that it's there.

Mender's Purity ; This can be a real life saver in certain situations. One major reason to use Ether Feast vs Signet of the Ether for the lower cooldown on Ether Feast.

Warden's Feedback ; The MAIN reason this tree is used as far as dungeons goes. This makes Phantasmal Warden reflect projectiles instead of just neutralizing them, which can put out some pretty nice damage. It also makes Temporal Curtain reflect a variety of projectiles as well, notably ground pathed or low path ones, and additionally some that come from a high upward arc. I get best results while standing right on top of the field, or slightly behind it.

Phantasmal Strength ; Very good use for 5 more points into this tree, almost no reason to pass this up. More damage.

Illusions ; Always been a somewhat hard to use tree in my opinion, due to having lowered shatter times. If it wasn't for Illusionists Celerity, there probably would be no points in this tree.

Illusionary Retribution ; Some extra damage onto your shatters. Not great, but basically free damage when you do use shatters.

Major Tier 1 ; Compounding Power is generally useful here, there are lots of fights that it is possible to make plenty of use out of this.
Master of Misdirection ; This could be useful in the same fights you would be using Ether Feast instead of Signet of the Ether, due to not being able to keep Illusions alive. This will make the confusion from Confusing Combatants last longer, or if you want to shatter instead, from Illusionary Retribution.

Illusionists Celerity ; 20% cooldown reduction across all weapons, for all illusion creating skills. Can't really beat that.

Phantasmal Haste ; This works out very nicely in most fights, as generally you can keep phants alive. This simply makes them attack 20% more often, so once every 4 seconds instead of 5 for instance. This is also very useful for fights where you can actually stack Warden vs immobile or ranged targets who don't move, increasing the reflect uptime. Basically has to compare to Domination's T1 Major Empowered Illusions. IMO with only 5 more points into the tree, you get something that is close to equivalent in ALMOST all situations, except for those where you can't keep phants alive. In that case, you could always swap to Illusionary Elasticity for some more bounces.