Okay, single target is plain easy. Use Shield Slam everytime it's off cooldown. Use revange everytime it's off cooldown. When Shield Slam and Revange is on Cooldown, use Devastate (when you use either Revange or Devastate, the talent Sword and Board have a chance to refresh your Shield Slam).
You will also want to macro most of your skills with Heroic Strike, since it is a skill that has no global cooldown.
Here is a page with Usefull macros for warriors.
I hope this was useful :)