The textbook E/A boss farmer looks something like this:
Earth Magic 12+1+3
Shadow Arts 12
Rest in Energy Storage
Shadow Form
Sliver Armor
Shadow of Haste
Death's Charge
Dark Escape
Glyph of Elemental Power
Optional
Optional
With a 20% enchant staff. Ditch the regen daggers (whatever that means).
General farming is not as well suited to the E/A, but you might try the typical stoneflesh aura / armor of earth / aura of restoration combo, with stone daggers / sliver armor and... maybe Assassin's Promise?
E/Me is much better for general farming, you can use stone striker/mantra of earth for unlimited energy and use echo'd sliver armor to wreak havoc.