That's a long discussion, but since you're already with dw on a tyrr, you obviously are going for skill setup. Focus on getting artifacts +10 (p.atk, p.cd, p.sp), also +11% skill power one. Focus more in skill power and P.atk than skill crit dmg in general.
Get a good level of shilien soul crystal, not sure how viable getting shil 8 on ncwest is, but that's the minimum imo.
Get your shirt augmented, at least 8% p.cd minimum there.
Get augmentes for skill crit rate, this is vital, the more you get, the better. Not sure what jewels you use, but if you can augmet them get p.skill crit rate will be great. Obviously you want them to give p.skill cd or direct damage.
Next is pve dmg, the more of it, the better. Get +5% on circlet, use bloody set, basically anything that can net you pve dmg is worth investing in.
There are many other things to consider, this just a very very short list.