Fire does ok damage if you have a Searing Touch. Just use 2 fire traps and fireball with conc effect and LMP or GMP. If you're having issues most likely it's a gear issue, like not having a 5L or a good searing touch. I'd use the 5L chest for fireball, like Fireball, Conc Effect, Faster Casting, Life Leech(with ghost reaver), LMP or GMP depending on tastes, I think I'd rather go LMP myself but I see most people going GMP, it's more dmg if you shotgun and more coverage. Then Searing Touch needs to have decently high mods and I'd put at least 2 fire traps in it. If you somehow can get a 5L though on it, I'd put fireball in it it's gonna do more dmg that way. Otherwise yeah get 2 fire traps so you can semi spam them, purity and discipline aura with clarity with the rest of the mana you have, decoy totem or skeletotem up to you, if you're close I'd grab the totem health node if going decoy, but skele should do the job without the need for it, enfeeble and flammability curses to use depending on the mobs and that should be fine.
For the build I'd probably start with something like that:
http://www.pathofexile.com/passive-s...-0Tm3GnliuWAc=
Then from there, depending on the numbers I end up with which I'm not too sure about since I haven't played CI yet, I'd invest the next 20points into the shadow starting area by the fastest path, or I would get the ES nodes in the middle grabbing the 3% cast speed on one side and the 40%mana regen on the other. Mana nodes are also based on assumption that they might be needed, which isn't necessarily the case I guess, but I'd want to run Purity/Discipline/Clarity at least so might need some mana. If the top big node isn't needed, can probably save 1point or something. Double curse might also not be needed so you could remove most of the points up there, grab Serpent Stance from the bottom instead. Stat points are also based on possibility, not necessity.
Standard build I think.