The deck is focused on getting Gandalf into play and keeping him there to use as a fourth hero. Mulligan for him, since he's the point of the deck; most of the rest of the deck is card draw to help you get him and threat reduction to help him stay in play; once you're in a good shape, a lot of that can benefit other players.
Once you have Gandalf, his toys can be very useful: Shadowfax lets other players benefit from him and gives him another action in combat; between that and Narya he should get to quest and then participate in combat three times. After his first use as a attacker/defender, use Narya to ready himself before resolving the attack so he gets the +1 and +1 for all three uses. It doesn't even really matter who the second ally is; if there's no one cross-table who would benefit, I just ready one of the questing allies for an extra point of . In a pinch Arwen Undómiel can defend against a small enemy, especially if you use Gandalf's Staff to get rid of shadow cards.
Events are pretty typical for and . Flame of Anor is mostly there as another ready for Gandalf. It will give an average of +1.5, but has a reasonable chance of whiffing entirely, so I wouldn't count on it for extra attack.
This deck obviously mostly spends resources, so Glorfindel should pay for the neutral cards. I originally had Aragorn in here as the lore hero, and perhaps Eleanor instead of Merry, but found Aragorn was overkill for keeping my threat low, and Glorfindel was a reliable way of keeping damage off Gandalf, since this deck isn't too resource-intensive once Gandalf and his toys are in play. Unexpected Courage, Light of Valinor and Hobbit Pony are there to give you more uses for your heroes' actions, and can also be played cross table. If you would rather, find space for Ioreth and replace Glorfindel with Pippin for more card draw and plenty of healing with lower threat (start in secrecy!) at the expense of Glorfindel's better stats and location control from Asfaloth. Or just use Ioreth with Messenger of the King.
u forgot that you need to exhaust the char with narya too, so, its 1 action less with gandalf, but still good. so, u have to be ready then use narya (and exhaust gandalf for it) ready him as part of naryas action and have a regular action with gandalf with +1 with shadowfax u have another action with bonus but thats 2 not 3.