For Dragoon, you can use skills from Marauder and Pug.

The only one I think you really need is Internal Release (Pug 12 -- crit rate +20% for 15 seconds). The one you definitely don't need is Skull Sunder (Mar 4 -- increases enmity ... bad for DRG).

You might want a couple of defensive abilities: Foresight (Mar 2 -- +defense 20%), Second Wind (Pug 8 -- instant self-heal), Bloodbath (Mar 8 -- 25% of your next attack as self heal), or Featherfoot (Pug 4 -- +evasion 15%). Mantra is good, but it's Pug 42, so you might not have that for a while.

And you might want an extra attack (if it doesn't mess up your rotation): I like Fracture (Mar 6 -- DoT that lasts a long time, so you don't need to reapply it very often). I'd probably pass on Haymaker (can only be used after evading an attack) and Mercy Stroke (very powerful attack, but you almost never get the self heal, and it's got a very long cooldown).