Icy Veins and WoWhead both have class guides - I prefer Icy Veins if only for the lesser amount of advertising and browser-killingness of it, if I leave it up.
But if you don’t want to look it up, this quote from Icy Veins sums it up:
Generally speaking, the stat priority should only be followed when comparing gear of the same item level. A piece of gear with a higher item level than what you currently have should be equipped regardless of its secondary stats.