Adoria´s Saboteur Guide (Ranged)

First of all, we need to chose our first class, which will be the Demolitionist.
The first Skills we focus on will be Firestrike and Explosive Strike.
Static Strike we can ignore safely. Splinter is important again, since it will add alot of piercing-damage
and fire-damage.
Later we chose Nightblade as the second Class, because Anatomy of Murder greatly suits our needs.

Grim Calculator Link [grimcalc.com]

So now we should have a plan about what its gonna be and we can start, right? Just level your character and chose the Demolitionist Role as your first one. Then directly put 1 point into Firestrike, so we can use it as our Main-Skill. Get one of those low-level Handguns and keep on grinding. With the first level up´s, go for some Physique, to assure being able to wear some good stuff at least. Then put all the Attribute-Points into Cunning, of course!

Lets take a look at our two Skill-Trees:

I wouldn´t recommend maxing Firestrike first, because it slows us down, getting to Explosive Strike, which is very nice to have as fast as possible. Don´t worry, you can put some points into that later, IF you really want. For the beginning focus on spending the points into the Demolitionist himself, the mighty big plus-sign!
When you can finally start putting some points into Explosive Strike, the fun begins! Now you can either max it directly level after level, or you could spend even more points into the Demolitionist himself, to get your Splinter earlier. It´s up to you! Meanwhile you have already chosen your second role as a Nightblade hopefully. When Explosive Strike and Splinter is finally maxed you can begin putting some points into the Nightblade himself (the mighty mighty plus-sign!) to get the Anatomy of Murder Skill.

If you got some decent gear by now your char could look like this:

As for the gear, look out for IAS, +Cunning, +Offensive, +(Fire?) DMG, + IMS <- makes kiting easier!