[3.2] Shadow Flicker Assasin dagger+shield

New to PoE and sorry to add probably yet another thread asking for advice, but here goes. I'm on vacation right now so can't provide much details but I have the time to research.

I'm playing as a Shadow Assasin using dagger and shield with Flicker Strike. So far I've not found a 5 or 6 slotted armor so I'm stuck using flicker with crit chance, splash dmg and multistrike.
I'm using Herald of Lightning. Shield charge. Curse on hit with Poacher curse. I'm using activated when dmg taken linked with Tempest Shield.

After searching the forums for a while I've found a few builds similar to what I am aiming for but nothing I can follow in terms of gear and passive skill tree so I'm going on instinct. Choosing passive skills for crit with dagger and lately increased dmg and armor when using shield.

Have done this one from what I remember since I'm not at my home-computer.
https://www.pathofexile.com/build/0oJnCz

Status:
- Lvl 64
- Dps 2.8 K
- Can quickly clear instances my lvl
- Have some troubles with survivability when meeting elite mobs
- Have no chance against bosses, luckily the friend I'm playing with can take care of them for me

What I need advice with:
- How to get better survivability
a) I only have one aura activated. Mana doesnt seem to be a problem.
b) I realize having just read some other threads I'm missing life % in my passive skill tree. Should that be priority?
- Gear (not sure how I can show you my current gear..)
Got mostly shit I picked up on the road. Some legendaries that I use - because they are legendaries but not really the stats I'm looking for. Should I farm a 5-6 slotted armor somewhere? Currently in act 9 if i remember correctly.
- Passive skill tree