Mono-Blue Terror is a permission-based tempo deck where Tolarian Terror and Cryptic Serpent become essentially free threats once the graveyard is stocked, so you need to contest their threats with Skred and your own countermagic while advancing your Ephemerate-Mulldrifter engine. Red Elemental Blast is a free roll that can counter a Counterspell, Brainstorm, Tolarian Terror, or Cryptic Serpent — it belongs in every blue matchup and is at its best here. Lightning Bolt is poor against 5-toughness threats and they rarely have legal targets, so trim it down; Ride's End bounces a creature they can simply replay for free given their low mana costs. Your longer game backed by Murmuring Mystic making tokens and Counterspell protecting your threats should win most drawn-out games, so stay patient and don't overextend into Force Spike.