So being as new as I am I have no clue what would make a viable build, especially to help you all out once I get high enough to run dungeons with you. I have a Ranger, Mesmer, and Warrior that I am splitting my time in. I saw that there are builds in the site that Retro linked but honestly I can't say which would be a better build over others. Any help on builds would be appreciated.
I will try to help with Mesmer builds.
My Phantasm build:
http://www.gw2db.com/skills/calc/me...1775|2228|0|2|17|0|0|0|0|0|0|0|0|0|0|0|0|0|0|
You can swap Greatsword for Staff if you want to add a bit more group support. Most like Ether Feast as a heal, but I've grown fond of Mirror for the reflect and low CD. If you're running Staff, then Chaos Armor + Activating Signet of Inspiration gives your group protection plus whatever else you have on. You will constantly have Vigor on you as well. The key is using your reflect skills well and rotating your Phantasms in after a window to shatter them.
Basic Shatter Build:
http://www.gw2db.com/skills/calc/me...27|1775|2309|7|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|
You can swap Focus in for Pistol if you like or need the speed boost. This build is all about shattering and doing so most commonly with a shatter combo. Generally, you always open with Diversion shatter with 3 illusions up, then follow with either Decoy, Mirror Images, and Mind Wrack Shatter when up close or iLeap, Mirror Images shatter up close. Always shatter up close to the target to get the 4x shatter effect, and save Mirror Images for the follow Mind Wrack Shatter. If you use Mirror Blade to create an Illusion for your first Diversion Shatter, you can easily have full vulnerability stacks on your target and 6-8 stacks of might on your Mind Wrack followup Shatter.
The Shatter build takes some quick input to do effectively. It can kill targets very fast, but you need to do five or six inputs quickly in succession. Say you open up with an iDuelist and iBerserker on your target. You toss a Mirror Blade at your target and start running towards it. When you are in melee range of your target, you switch to MH Sword/Pistol, hit F3, hit 8, hit 9, hit F1, and follow with 2 for added damage. It's best if you snare your target, so to do that you would toss the mirror blade, run in to get into melee range, tidle to switch weapons, hit F3, hit 3, hit 3 again to swap and snare, hit 9, hit F1 and hit 2 for Blurred Frenzy.