Sneak attack combined with Spot the Weak point

[StreamOfTheSky]

If your are an uncanny trickster you can favorit this trick allowing you to do it twise every encounter

Or...for the same action cost (standard action one round to set up one devastating attack the next round), you could just Use Magic Device a Wand of True Strike, and unless the creature has armor, shield, and natural armor bonuses of 20 or greater adding to C, actually have a better chance of hitting. Useable as many times as you want, no need for a skill trick or prestige class levels.

 

[StreamOfTheSky]

Now, wands of Wraithstrike are a dirty trick. (And persisted Wraithstrike is just cheesy)

1. Wraithstrike itself is dirty, though Persist Spell feat is, as well. Both should be banned.

2. It's only actually cheesy on a wand if you use Rules Compendium. I do not when I am DM. All wands cost a minimum of a standard action to activate, making Wand of Wraithstrike useless and a Wand of Extended Wraithstrike costly compared to True Strike (though it can benefit a full attack, so the higher price is warranted).

 

[irdeggman]

If you are "hidden" from your target you are considered "invisible" against that target.

Thus they are denied their Dex bonus to AC and you get a +2 on your attack as well.