-The key to this deck is being able to operate on your opponents turn.
-Control the board at all costs; you'll likely need some red instants early on to delay the game long enough until you can get enough mana to overtake your opponent.
-Try to avoid using duplicate spells until Pyromancer Ascension is in play (although it will become inevitable at times).
-You should have 3-4 land around turn 5-6, allowing you to zap your opponents board while still maintaining land to counter any new threats they might try to throw down. Use Ponder and Preordain to dig up land to meet this mana threshold.
-With a little luck, the ascension will be activated by this point and your red spells will hit like trains. If not, your Ponders and Preordains work just as well toward this goal. The ascension also copies your cantrips, which now draw two, giving you the card advantage you need to overwhelm your opponent for the win.
-The low land content of the deck also means that you can expect your opponent to continue regularly drawing land in the late game while you are drawing crucial spells. And the no-creature policy means that any cards targeting creatures your opponent has will either be seriously diminished or altogether useless against you.
-If you get the cards you need, and you are able to adequately control the game, you can expect to win between turn 12 & 14.
SIDEBOARD:Be wary of threats to your Pyromancer Ascension. Spell Pierce is nice because the ascension increases it's effectiveness (multiple copies can target the same spell). However, sometimes ransoming their destroy spells for mana may not be enough, in which case an outright counter (Negate) may be more appropriate. If you suspect that your Pyromancer Ascension is coming under fire, don't hesitate add a fourth copy.
Slagstorm may be a more effective board clear for decks that have beefier mid-game creatures, if your other spells are struggling to maintain a clear board on their own. Slagstorm also offers the ability to race down your opponents health if push comes to shove.
Into the Roil, Void Snare, and Cyclonic Rift are all great for dealing with pesky non-creature threats. I went with Into the Roil for the optional cantrip, but Void Snare may be better for its lower cost, and Cyclonic rift has some nice Izzet flavor and has extra late-game options. Use it to return an enchantment or artifact before countering it with a Negate or a Spell Pierce effect when they try to bring it back out. It's also handy when facing protection from red.