Life gain deck

Hey i need some help with this deck. A friend of mine introduced me to magic recently and im not very experienced in magic deck building and need some advice. So this deck is a white and blue deck. The main point is to have me gain life while my opponent loses it. Currently my deck has quite a few flying creatures. My deck also needs to be able to help counter my opponents moves with negation cards. Please list any suggestions in the comments. Thanks!

Ajani Goldmane (planeswalker)
Silent Sentinel
Griptide
Mortal's Ardor x2
Nyxborn Shieldmate
Loyal Pegasus
Nyxborn Triton x2
Glorious Charge
Hold at Bay
Excoriate
Traveling Philosopher x2
Hopeful Eidolon
Heliod's Emissary
Ordeal of Heliod x2
Jace's Pbantasm
Aerial Maneuver
Pillar of War x2
Unsummon
Safe Passage
Divination x2
Elixar of Immortality
Gift of Immortality
Flitterstep Eildolon
Coastline Chimera
Cloudfin Raptor
Lagonna-Band Elder
Ghostblade Eidolon
Basilica Guards
Essence Scatter
Island (blue) x11
Plains (white) x17

I've only been playing Magic for a few months, but here's my opinion: if you want to gain life and have your opponent lose life, don't go white/blue. IMO you would want to go white/red.

There's also a fun mechanic that fits your goal called "extort," where when you play a spell, you can tap mana to have your opponent lose 1 life and you gain 1 life. I'd recommend you check that out.