Please Help Me Die Less

In general:
* Keep resists as high as possible. Have rings in your inventory that you can switch out to get to max (or close to) when you need it for specific areas

* You probably also need to get some better gear. More defense, more life on gear (energy shield), higher resists


Mara
* Stack life on the mara.. then stack more life.. and life regen. Help Oak on the bandit quests for more life. Get lots of life on gear. Life is king, eat them life nodes like candy.

* Consider Resolute Technique also Blood Magic when you have lots of life regen

* Later on get "Elemental Adaptation" to increases your max resists

* Note: as melee life char you'll constantly be taking damage so the "melee damage on full life" gem is practically useless for your build. This gem is only useful with a large energy shield buffer so your char is always at 100% life.

Witch
* For a crit build it's better to head towards the shadow area as there are lots of crit and crit damage nodes along the way and around shadow. Also lots of energy shield nodes in the Nullification clusters.

* Consider a fireball totem with multiple projectiles

EDIT: generally people take CI when their ES (with discipline aura) is at least twice their life pool (otherwise you lose more life then you gain ES)... or they wait until 2k buffed ES as there are no potions to restore ES like you can with life.

Chamber of Sins:
* Must have max or near max lightning resist, especially for Fidelitas as even with capped resists he can 2 or 3 shot you with high life.

* Have some means of destroying corpses (raise zombie, detonate dead, cold crits) so the necros can't raise them against you

* Fidelitas: curse him, use totems and/or minions to distract him so you have more chances to DPS him