MTG Salvation

If you really want my suggestions, then here I go:
Platinum Angel is too vulnerable. It dies to a well-placed Burst Lightning with kicker cost paid in full, or a Path to Exile, Journey to Nowhere, or Oblivion Ring, (Path to Exile is majorly popular in white standard.)
Planar Cleansing is probably not something you really want. Consider Martial Coup instead. White is all about creature-advantage, and if you clear the field, you and your opponent are almost on equal levels (depending on what's in your hand.)
I will say that white lifegain has never been majorly popular in anywhere outside of casual. It tends to be slow, and lifegain tends to want to stall the game.
Find more honor of the pure. They're going to be what this deck ultimately needs. It's definitely a 4 of.
Consider removing the Gleam of Resistance in place of an Honor of the Pure. Its effect stays on the field longer, and ultimately it has more applications for your deck as a result.
Take out Kazandu. If you're only running a copy, his effect isn't going to benefit you (especially since you're running so few allies.)
Valiant Guard is probably not something you absolutely need.
I like World Queller, but he's just too darn vulnerable.
If you're on a lower budget, sigiled paladin is probably a 4 of.
Also, the Palace Guard can probably go...
your deck needs bigger threats than what it has now. Since lifegain is a plus for you, but not necessarily devastating to your opponent, you might want to focus on more than just lifegain as a strategy. I like that you've got O-ring and Path in there- that's the kind of thinking you need. Just try to focus on how you're going to stop your opponent as quick as possible, rather than stalling them, because ultimately, there are some really fast decks out there.