This deck is meant to complement a Celeborn Leadership/Lore silvan deck. Celeborn complements Galadriel bonus to the few silvan allies in the deck, though allowing Gandalf to quest for free is probably the most useful ability.
Dori will primarily buff the defense of one of the heroes in the other deck, while Legolas and his ranged supporters will kill the enemies engaging the other deck. The attachments are a mix of defense /questing boosters, weapons for Legolas (or the archers, once Legolas has two restricted). In the initial hand you want Nenya to let Galadriel contribute to questing, or Light of Valinor to let Celeborn quest and defend -- but getting any kind of weapon and Foe-hammer can also be worth keeping by itself. And as always, an initial A Test of Will can save an otherwise unimpressive hand.
Mirror of Galadriel and Silver Harp work extremely well together, so if you get the Mirror look for the harp. Heed the Dream in the other deck can also help get those two together. Errand-rider in the other deck can also help bolster Galadriel's resources.
Children of the Sea and Island Amid Perils are useful more for popping the allies in and out of play than their direct effect. All the Silvan allies have useful effects.
The sideboard has Arod for location control, The Galadhrim's Greeting and Double Back for threat, Hasty Stroke for particularly nasty shadows, and Feint and Hands Upon the Bow for particularly combat-focused quests.