Starting a mesmer, Used to playing Elementalist, help?
If survival is an issue look for toughness. You have a lot more hp than an elementalist, take advantage of that. Also between clones (not phantasms), dodging, and circle strafing, you can be hard to hit in the first place. Traits can make a difference too. I noticed a big difference with the one that gives protection when you get regeneration.
If you like GS kiting is key. The phantasm cripples, which helps. So does the trait for cripple on clone death, since GS clones spawn on the target. For the sword, blurred frenzy is your best defense, time it right. Most off hands also bring something defensive. On pistol you have magic bullet, which can buy time. Also think about focus for the AoE pull/knockdown, or sword for the block.
For a different option, the staff is a great tanky weapon. Chaos Armor only works when you are taking hits. If you drop Chaos Storm on yourself and clones, you’ll last a lot longer. And if you auto attack close to your target you’ll stack might and fury on yourself – dead opponents can’t kill you.