The best Mesmer build for farming is to get a Guardian. No seriously, we aren’t that great at farming. The best thing about our farming is at least it is less boring then most grinds.
You probably want a shatter build since in PvE clones are a lot more effective at drawing fire. Confusion is fairly meh since most enemies swing at the rate of once every 3 seconds which bypasses a lot of non-extended confusion(thanks Anet), even worse on slow swinging enemies like Ogres, they might even get hit once. That pretty much throws Scepter under the bus, most the rest of them are viable though. Personally for farming I like Greatsword with Sword/Torch when they get close or in large groups. You can also do Pistol for a bit faster DPS but The Prestige can save your butt if you accidently pull too many and gives you another good AoE damage. Off Hand Sword has a strong phantasm and you can do a lot of damage if you time your block well but once again, no AoE. Staff is slowest at killing but can make you a bit more survivable too.
I’d have 5-15 in Domination so your interrupts stack vuln, 20 in Dueling so you make clones when you dodge. Getting both 15 in Chaos and Inspirations gives you pretty much permanent regen and 3 seconds of protection every 15 seconds. Chaos is also nice for when you need to jump off a high jump and not die. Put whatever you have left in Illusions to max your shatter damage and shorten the cooldown, lots of good stuff in there.
Ergg, now I read that you want to do dungeons, um, Staff is everyone’s friend, Signet of Inspirations makes it better, everyone loves Time Warp and Mantra healing(20 points in Inspirations with Mantra of Distraction/Pain) will make you indispensable.
“We are the makers of the music, we are the dreamers of the dream”
-Willy Wonka(Gene Wilder)
im unexperienced in terms of farming, I usally play pvp
And, I guess it’s dungeons, if it’s not, im open other options