You need a 1.30 dagger which is bis for Vael. The best 3 in order are:
Julie’s is easy to get. Costs around 9g on AH. Better if you get lucky on a Finkle’s or you can afford Alcor’s (1k on my server atm). Enchant with Crusader.
This is for a deep prot spec (14/5/32) with 3/3 Imp HS:
I would use that spec for the first few weeks regardless even if you prefer playing fury/prot, since BWL may be overtuned compared to private servers.
If you do prefer to play fprot, then just change out Shield Slam for Bloodthirst.
Vael rotation is all about HS spam with a 1.30 speed dagger since you have infinite rage. You will also want a +dagger item like ACLG, Edgemaster’s or Mugger’s Belt so you can just hit cap at 6% instead of 9% and not suffer glancing blows penalty.
If youre not the main tank, then sit at the proper order spot on threat till its your turn (toggling macro on and off to stay in your threat slot). When the current tank dies, get into position right away, popping Recklessness, and go to town. Ideally you will have pooled a little rage just before.
If you are the main tank from the start of the fight, pop Recklessness on the pull.
Ctrl to Shield Block (shouldnt need it unless you want to proc a Revenge or youre really low on hp), Alt to HS if you want to queue another sooner than waiting for Sunder gcd.
Run at 30-50 ms.