A rotation-proof Jeskai shell. Key cards are:

This particular version is for BO1, but a sideboard for a BO3 version that adapts to major meta-decks should be pretty easy to build.  Please leave sideboard suggestions in the comments.

Please leave any advice to tweak this version for BO1 in the comments as well.

There are basically two ways to win -

1) Massive amounts of direct damage to the face.  Works best with Fiery Emancipation (The Nuclear Option):

• Once Fiery Emancipation is active, Sundering Stroke and Inspired Ultimatum can be game enders.  21 points of damage is a tough turn for anyone.  15 points with 5-card draw isn't so easy to recover from either.
• Narset of the Ancient Way Ultimate with Fiery Emancipation is a "spell clock," and there are plenty of low-cost spells.

2) A flood of Sharks (War of Attrition):

• Whirlwind of Thought provides constant fodder for Shark Typhoon allowing you to match creature output. 
• With Fiery Emancipation down, every Shark becomes a serious threat.  And there are lots of big spell (4+ CMC) to cast for hard-hitting sharks, but even 1-3 CMC Sharks swing above their weight class.  Kamikaze the Sharks.

How to Mulligan - 

Keepers:

• 3+ lands AND every color is represented
• 3+ lands w/ castable Revitalize AND cheap removal (Shock, Fateful End, Soul Sear, Fire Prophecy)
• 3+ lands w/ Shatter the Sky
• 2+ lands w/ multiple, T2/T3 castable copies of Revitalize

General Playing Guide - 

• Do everything you can to have 2x Plains ready to cast a turn-4 Shatter the Sky
• It's important to hit land drops at least to turn 7.  After this, every draw is a potential two-turn clock (Fiery Emancipation + Sundering Stroke)
• Get 7 red sources ASAP.  This maximizes damage output from Sundering Stroke.
• Usually one Whirlwind of Thought is enough.  Once you play two of them, you're basically on a clock before you self-mill.  In this build, Whirwind of Though is an engine, not a combo card.  Think of it more like cycling, except you get to play the spell.  I've never had three on the board at once, and don't see the need, unless I wanted to combo with eg, Dream Trawler, as the draw is far too much.  With a Whirlwind of Thought on the board, the others can be discarded to Narset of the Ancient Way
• There's quite a bit of incidental life gain built into the deck.  Between Narset of the Ancient Way, 4x Revitalize and tap lands, don't be afraid to take some damage to maximize the value of cards like Shatter the Sky, Soul Sear, Elspeth Conquers Death etc.
• Kaheera, the Orphanguard is a free card that can be cycled with Fire Prophecy, chump blocker or Narset of the Ancient Way discard.  It's usually safe to put it in-hand on turn 3.

Against Mono-Red:  Prioritize tap land life gain, aggressively cast Revitalize and maximize the value of Shatter the Sky.  After the first Shatter the Sky, use spot removal to stall until you draw a win-con.  Shark Typhoon is particularly effective with spot removal.

Against Temur Adventures:  This matchup is a race and not an easy one.  Get Whirlwind of Thought on the board ASAP to keep up with card advantage.  Sadly, you can't use Elspeth Conquers Death on Lucky Charm.  Banishing Light works until they draw Brazen Borrower.  Try to have the burn in-hand before playing Fiery Emancipation, to minimize Brazen Borrower interference.  (*To tailor this deck against Temur Adventures, replace minor burn spells with counterspells and/or artifact hate.  Could probably replace Chandra, Heart of Fire and something else with a pair of Dream Trawler or some other high-end creature threat.)

Against counterspell control & flash decks: Stack land and craft your hand with burn to pull counterspells, then drop a threat Fiery Emancipation or Shark Typhoon when the opponent is tapped.  Basically, get in where you fit in, but it's not a fun matchup.

Against Removal Heavy Control: Laugh all the way to the bank.

Against Stompy and everything else: Play for value, remove major threats until a win-con hits the board.