If you want to beatdown with blue, use blue's larger creatures with flying (just hold counters for the inevitable Hurricane(s)).
You have not specified what type, nor if its for multiplayer or duelling, so I will presume multiplayer, type casual...
Mahamoti Djinn is your first step. He'll even survive your splashed Wave of Reckoning (unlike your other creatures).
If you keep things blue and white, though, you'll need artifact mana to speed things up a tad. I recommend Sol Ring, Mana Vault(s), or the Thran equivalent to the Mana Vault.
Air Elementals are decent, and easy to get ahold of, so they should stay. Though not terribly huge, the card drawing of the Thieving Magpie should not be overlooked. Nor should the library manipulation of the Spire/Sage Owls (plus they are early drops).
Cloudskates come out early, though they fade... but timely Unstable Mutations render that moot.
So we come to...
4x Mahamoti Djinn
4x Air Elemental
4x Theiving Magpie
4x Cloudskate
4x Spire/Sage Owl
4x Unstable Mutation
4x Counterspell
4x Forbid
4x Unsummon or Seal of Removal
4x Thran mana generator (costs 4, makes 3 when tapped)
1x Sol Ring
16x Island
4x Faerie Conclave
For a total of 61 cards, though mono blue. Splashing for white would require the removal of blue utility (I recommend 1x Forbid, 1x Counterspell for 2x Waves of Reckoning, and 2x Unsummon/Seal of Removal for 2x Disenchant variant of your preference. To support it, replace 1x Faerie Conclave and 2x Islands with 3x Coastal Tower).
Most of your creatures will die to a Wave of Reckoning, but the Magpies and Djinns live through it, to deal damage, accordingly...
Maybe that helps?