In no particular order:

Trailblazer's Boots.

Mizzium Mortars.

Sigarda, Host of Herons and Gisela, Blade of Goldnight.

Clifftop Retreat, Rogue's Passage, all 3 shock lands in color. Also filter lands - Rugged Prairie, Fire-Lit Thicket, and Wooded Bastion.

Beastmaster's Magemark.

Eldrazi Conscription.

Rush of Blood or Berserk.

Fireshrieker or Rage Reflection.

Big bloodrush creatures like Rubblehulk or Skarrg Goliath.

Fling effects, maybe through Brion Stoutarm or Bloodshot Cyclops.

I think you can get a lot of mileage out of tuck effects simply because you're playing white.

I suggest Oblation and Condemn. There are times when giving an opponent 2 cards also means shutting down their entire deck (if you play against any general-centric decks).

There are a couple of weak cards (or suboptimal ones) like the keyrune, Divine Verdict, and Steward of Valeron, but this list is very solid over all.

I do think you could use more land, lowest being 35-36, and some mana ramp in the form of Solemn Simulacrum or Explosive Vegetation. Maybe even Sakura-Tribe Elder and Wood Elves.

I've been working on an Uril, the Miststalker EDH deck as well.

http://tappedout.net/mtg-decks/aurafield-looking-for-advice/

Draw is one of the biggest things in EDH. I'm trying to get more draw creatures in my deck. Some that were suggested to me were Verduran Enchantress , Argothian Enchantress , and Enchantress's Presence .

If you're running Indestructibility then you may as well run Pariah . Such a great combo. Gives you a second option to the Palisade Giant .

Asceticism wouldn't hurt. I see Privileged Position , but the regenerate ability on Asceticism can be handy.

Think about adding a Kessig Wolf Run as well. It made a huge difference in my games. Also since you are using W/R, a Boros Charm would never be a bad thing.